Edgar Filing: NATURAL GAS SERVICES GROUP INC

Large accelerated filer

Accelerated filer

Non-accelerated filer

¨ (Do not check if a smaller reporting company)

Smaller reporting company

Form S-3

As filed with the Securities and Exchange Commission on October 31, 2012

Registration No. 333-

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM S-3

REGISTRATION STATEMENT

UNDER

THE SECURITIES ACT OF 1933

LOGO

NATURAL GAS SERVICES GROUP, INC.

(Exact name of registrant as specified in its charter)

Colorado

75-2811855

(State or other jurisdiction of

incorporation or organization)

(I.R.S. employer

identification no.)

508 West Wall Street, Suite 550

Midland, Texas 79701

(432) 262-2700

(Address, including zip code, and telephone number, including area code, of registrant’s principal executive offices)

Stephen C. Taylor, Chief Executive Officer

508 West Wall Street, Suite 550

Midland, Texas 79701

(432) 262-2700

(Name, address, including zip code, and telephone number, including area code, of agent for service)

The Commission is requested to send copies of all communications to:

David A. Thayer, Esq.

Jones & Keller, P.C.

1999 Broadway, Suite 3150

Denver, CO 80202

Telephone: (303) 573-1600

Facsimile: (303) 573-0769

Approximate date of commencement of proposed sale to the public: from time to time after this registration statement becomes effective as determined by market conditions and other factors.

If the only securities being registered on this Form are being offered pursuant to dividend or interest reinvestment plans, please check the following box. ¨

If any of the securities being registered on this Form are to be offered on a delayed or continuous basis pursuant to Rule 415 under the Securities Act of 1933, other than securities offered only in connection with dividend or interest reinvestment plans, check the following box. x

If this Form is filed to register additional securities for an offering pursuant to Rule 462(b) under the Securities Act of 1933, please check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering. ¨

If this Form is a post-effective amendment filed pursuant to Rule 462(c) under the Securities Act, check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering. ¨

If this Form is a registration statement pursuant to General Instruction I.D. or a post-effective amendment thereto that shall become effective upon filing with the Commission pursuant to Rule 462(e) under the Securities Act, check the following box. ¨

If this Form is a post-effective amendment to a registration statement filed pursuant to General Instruction I.D. filed to register additional securities or additional classes of securities pursuant to Rule 413(b) under the Securities Act, check the following box. ¨

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, or a smaller reporting company. See the definitions of “large accelerated filer,” “accelerated filer” and “smaller reporting company” in Rule 12b-2 of the Exchange Act.

Calculation of Registration Fee


Title of Securities (1)	Aggregate offering price (2)		Amount of registration fee (3)
Common Stock		--		--
Preferred Stock		--		--
Depositary Shares		--		--
Debt Securities		--		--
Rights		--		--
Units		--		--
Warrants		--		--
Total	$	150,000,000	$	20,460

(1)

Any securities registered hereunder may be sold separately or as units with other securities registered hereunder. The securities which may be offered pursuant to this Registration Statement include, pursuant to Rule 416 of the Securities Act of 1933, as amended (the “Securities Act”), such additional number of shares of the registrant’s common stock that may become issuable as a result of any stock split, stock dividends or similar event. In the event the registrant elects to offer to the public fractional interests in its shares of preferred stock registered hereunder, depositary shares, evidenced by depository receipts issued pursuant to a deposit agreement, will be distributed to those persons purchasing fractional interests and the shares of preferred stock will be issued to the depository under any such agreement.

(2)

An indeterminate aggregate offering price and number or amount of the securities of each identified class is being registered as may from time to time be sold at indeterminate prices, with a maximum aggregate offering price not to exceed $150,000,000. Separate consideration may or may not be received for securities that are issuable upon conversion of, or in exchange for, or upon exercise of, convertible or exchangeable securities. The proposed maximum aggregate offering price for each class of securities to be registered is not specified pursuant to General Instruction II.D of Form S-3.

(3)

All of the $150,000,000 of securities registered pursuant to this registration statement (collectively, the “Unsold Securities”) consist of unsold securities previously registered by the Registrant on its Registration Statement on Form S-3 filed on August 14, 2009 and declared effective on November 24, 2009 (File No. 333-161346) (the “Prior Registration Statement”). As of the date hereof, all of the Unsold Securities remain unsold. Pursuant to Rule 415(a)(6) under the Securities Act of 1933, the $8,370 registration fee previously paid by the Registrant in connection with the Unsold Securities will be used to offset the current fee of $20,460. As a result, an additional filing fee of $12,090 is being paid herewith. In accordance with applicable rules of the Securities and Exchange Commission, the Registrant may continue to offer and sell the Unsold Securities during the grace period afforded by Rule 415(a)(5) under the Securities Act of 1933, and, if the Registrant sells any of the Unsold Securities during that grace period, then the Registrant will identify in a pre-effective amendment to this registration statement the new amount of the Unsold Securities to be carried forward to this registration statement. Pursuant to Rule 415(a)(6) under the Securities Act of 1933, the offering of the Unsold Securities registered under the Prior Registration Statement will be deemed terminated as of the date of effectiveness of this registration statement.

The Registrant hereby amends this registration statement on such date or dates as may be necessary to delay its effective date until the Registrant shall file a further amendment which specifically states that this registration statement shall thereafter become effective in accordance with Section 8(a) of the Securities Act of 1933 or until the registration statement shall become effective on such date as the Commission, acting pursuant to said Section 8(a), may determine.

The information in this preliminary prospectus is not complete and may be changed. We may not sell these securities until the registration statement filed with the Securities and Exchange Commission is effective. This preliminary prospectus is not an offer to sell these securities and it is not soliciting an offer to buy these securities in any state or jurisdiction where the offer or sale is prohibited.

Subject to Completion, dated October 31, 2012

PROSPECTUS

$150,000,000

LOGO

Common Stock

Preferred Stock

Depositary Shares

Debt Securities

Rights

Units

Warrants

We may offer and sell from time to time under this prospectus an indeterminate number of shares of our common stock, preferred stock, depositary shares, debt securities, rights to purchase common stock, units consisting of two or more of these classes or series of securities and warrants to purchase any of the other securities that may be sold under this prospectus. We will describe in a prospectus supplement the securities we are offering and selling, as well as the specific terms of the securities.

We may offer these securities in amounts, at prices and on terms determined at the time of offering. We may sell the securities directly to you, through agents we select, or through underwriters and dealers we select. If we use agents, underwriters or dealers to sell the securities, we will name them and describe their compensation in a prospectus supplement.

Our common stock is quoted on The New York Stock Exchange under the symbol “NGS.” On October 26, 2012, the last reported sale price of our common stock was $15.46 per share. The applicable prospectus supplement will contain information, where applicable, as to any other listing on the NYSE or any other securities exchange of the securities covered by the prospectus supplement.

We may amend or supplement this prospectus from time to time by filing amendments or supplements as required. You should read this entire prospectus and any amendments or supplements carefully before you make your investment decision.

Investing in our securities involves certain risks. You should carefully consider the matters set forth in “Risk Factors” on page 5 of this prospectus and in the applicable prospectus supplement, along with any risk factor information incorporated by reference herein for certain risks you should consider. You should read the entire prospectus carefully before you make your investment decision.

Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities or passed upon the adequacy or accuracy of this prospectus. Any representation to the contrary is a criminal offense.

The date of this prospectus is , 2012.

TABLE OF CONTENTS


FORWARD-LOOKING STATEMENTS			1

ABOUT THIS PROSPECTUS			1

INFORMATION ABOUT NATURAL GAS SERVICES GROUP, INC.			4

RISK FACTORS			5

DESCRIPTION OF COMMON STOCK AND PREFERRED STOCK			6

DESCRIPTION OF DEPOSITARY SHARES			10

DESCRIPTION OF DEBT SECURITIES			14

DESCRIPTION OF RIGHTS			25

DESCRIPTION OF UNITS			26

DESCRIPTION OF WARRANTS			26

USE OF PROCEEDS			26

RATIO OF EARNINGS TO FIXED CHARGES			27

PLAN OF DISTRIBUTION			27

LEGAL MATTERS			29

EXPERTS			29

TRANSFER AGENT AND REGISTRAR			30

INCORPORATION OF CERTAIN INFORMATION BY REFERENCE			30

DISCLOSURE OF COMMISSION POSITION ON INDEMNIFICATION FOR SECURITIES ACT LIABILITIES			31

You should rely on the information contained in this prospectus. We have not authorized anyone to provide you with information different from that contained in this prospectus. Offers to sell the securities will be made only in jurisdictions where offers and sales are permitted. The information contained in this prospectus is accurate only as of the date of this prospectus, regardless of the time of delivery of this prospectus or of any sale of the securities.

-i-

FORWARD-LOOKING STATEMENTS

Certain statements contained in this prospectus are not statements of historical fact and constitute forward-looking statements within the meaning of the Private Securities Litigation Reform Act (the “Act”), including, without limitation, the statements specifically identified as forward-looking statements within this prospectus. Many of these statements contain risk factors as well. In addition, certain statements in future filings by the Company with the Securities and Exchange Commission, in press releases, and in oral and written statements made by or with the approval of the Company which are not statements of historical fact constitute forward-looking statements within the meaning of the Act. Examples of forward-looking statements, include, but are not limited to: (i) projections of revenues, income or loss, earnings or loss per share, the payment or non-payment of dividends, capital structure, and other financial items, (ii) statements of our plans and objectives by our management or Board of Directors including those relating to planned development of our natural gas compression business, (iii) statements of future economic performance and (iv) statements of assumptions underlying such statements. Words such as “believes,” “anticipates,” “expects,” “intends,” “targeted,” “may,” “will” and similar expressions are intended to identify forward-looking statements but are not the exclusive means of identifying such statements.

Such forward-looking statements speak only as of the date on which such statements are made, and the Company undertakes no obligation to update any forward-looking statement to reflect events or circumstances after the date on which such statement is made to reflect the occurrence of unanticipated events.

ABOUT THIS PROSPECTUS

This is only a summary and does not contain all of the information that you should consider before investing in our common stock. You should read the entire prospectus carefully, including the “Risk Factors” section as well as the information incorporated by reference into this prospectus under “Incorporation of Certain Information by Reference—Where You Can Find More Information.”

In this prospectus, the terms “company,” “we,” “us,” and “our” refer to Natural Gas Services Group, Inc., a Colorado corporation.

-1-

This prospectus is part of a registration statement that we filed with the Securities and Exchange Commission utilizing a shelf registration process. Under the shelf registration process, we may offer shares of our common stock, preferred stock, depositary shares, various series of debt securities, rights, units and warrants to purchase any of such securities with a total value of up to $150,000,000 from time to time under this prospectus at prices and on terms to be determined by market conditions at the time of offering. This prospectus provides you with a general description of the securities we may offer. Each time we offer a type or series of securities, we will provide a prospectus supplement that will describe the specific amounts, prices and other important terms of the securities, including, to the extent applicable:

•

designation or classification;

•

aggregate principal amount or aggregate offering price;

•

maturity;

•

original issue discount, if any;

•

rates and times of payment of interest, dividends or other payments, if any;

•

redemption, conversion, exchange, settlement or sinking fund terms, if any;

•

conversion, exchange or settlement prices or rates, if any, and, if applicable, any provisions for changes to or adjustments in the conversion, exchange or settlement prices or rates and in the securities or other property receivable upon conversion, exchange or settlement;

•

ranking;

•

restrictive covenants, if any;

•

voting or other rights, if any; and

•

important federal income tax considerations.

A prospectus supplement may include a discussion of risks or other special considerations applicable to us or the offered securities. A prospectus supplement may also add, update or change information in this prospectus. If there is any inconsistency between the information in this prospectus and the applicable prospectus supplement, you must rely on the information in the prospectus supplement. Please carefully read both this prospectus and the applicable prospectus supplement together with additional information described under the heading “Incorporation of Certain Information by Reference—Where You Can Find More Information.” This prospectus may not be used to offer or sell any securities unless accompanied by a prospectus supplement.

The registration statement containing this prospectus, including exhibits to the registration statement, provides additional information about us and the common stock offered under this prospectus. The registration statement can be read at the SEC website or at the SEC’s public reading room mentioned under the heading “Incorporation of Certain Information by Reference—Where You Can Find More Information.”

We have not authorized any underwriter, broker-dealer, salesperson or other person to give any information or to make any representation other than those contained or incorporated by reference in this prospectus and the accompanying supplement to this prospectus. You must not rely upon any information or representation not contained or incorporated by reference in this prospectus or the accompanying prospectus supplement. This prospectus and the accompanying supplement to this prospectus do not constitute an offer to sell or the solicitation of an offer to buy securities, nor do this prospectus and the accompanying supplement to this prospectus constitute an offer to sell or the solicitation of an offer to buy securities in any jurisdiction to any person to whom it is unlawful to make such offer or solicitation. We may also authorize one or more free writing prospectuses to be provided to you that may contain material information relating to these offerings. The prospectus supplement and any related free writing prospectus that we may authorize to be provided to you may also add, update or change information contained in this prospectus or in any documents that we have incorporated by reference into this prospectus. To the extent there is a conflict between the information contained in this prospectus and the prospectus supplement or any related free writing prospectus, you should rely on the

-2-

information in the prospectus supplement or the related free writing prospectus; provided that if any statement in one of these documents is inconsistent with a statement in another document having a later date — for example, a document incorporated by reference in this prospectus or any prospectus supplement or any related free writing prospectus — the statement in the document having the later date modifies or supersedes the earlier statement.

We may sell the securities directly to or through underwriters, dealers or agents. We, and our underwriters or agents, reserve the right to accept or reject all or part of any proposed purchase of securities. If we do offer securities through underwriters or agents, we will include in the applicable prospectus supplement:

•

the names of those underwriters or agents;

•

applicable fees, discounts and commissions to be paid to them;

•

details regarding over-allotment options, if any; and

•

the net proceeds to us.

-3-

INFORMATION ABOUT NATURAL GAS SERVICES GROUP, INC.

We are a leading provider of small to medium horsepower compression equipment to the natural gas industry. We focus primarily on the non-conventional natural gas production business in the United States (such as coal bed methane, gas shale and tight gas), which, according to data from the Energy Information Administration (“EIA”), is the single largest and fastest growing segment of U.S. gas production. We manufacture, fabricate and rent natural gas compressors that enhance the production of natural gas wells and provide maintenance services for those compressors. In addition, we sell custom fabricated natural gas compressors to meet customer specifications dictated by well pressures, production characteristics and particular applications. We also manufacture and sell flare systems for oil and gas plant and production facilities.

The vast majority of our rental operations are in non-conventional natural gas regions, which typically have lower initial reservoir pressures and faster well decline rates. These areas usually require compression to be installed sooner and with greater frequency. Natural gas compressors are used in a number of applications for the production and enhancement of gas wells and in gas transportation lines and processing plants. Compression equipment is often required to boost a well’s production to economically viable levels and enable gas to continue to flow in the pipeline to its destination.

We maintain our principal offices at 508 W. Wall St., Suite 550, Midland, Texas 79701 and our telephone number is (432) 262-2700. Our website is located at http://www.ngsgi.com. The information on or that can be accessed through our website is not part of this prospectus. We were incorporated in Colorado on December 17, 1998.

-4-

RISK FACTORS

Any investment in our securities involves risk. You should consider carefully the risk factors described in our periodic reports filed with the SEC (including the risks, uncertainties and assumptions discussed under the heading “Risk Factors” included in our most recent annual report on Form 10-K, as such may be revised or supplemented prior to the completion of this offering by more recently filed quarterly reports on Form 10-Q, each of which is or upon filing will be incorporated herein by reference), which may be amended, supplemented or superseded from time to time by other reports we file with the SEC in the future, and those identified in any applicable prospectus supplement, as well as other information in this prospectus and any applicable prospectus supplement and the documents incorporated by reference herein before purchasing any of our securities. Each of these risk factors could adversely affect our business, operating results and financial condition, as well as adversely affect the value of an investment in our securities. Additional risks and uncertainties not presently known to us or that we currently deem immaterial may also impair our business operations.

-5-

DESCRIPTION OF COMMON STOCK AND PREFERRED STOCK

The following description of our common stock and preferred stock, together with any additional information we include in any applicable prospectus supplement or any related free writing prospectus, summarizes the material terms and provisions of our common stock and the preferred stock that we may offer under this prospectus. While the terms we have summarized below will apply generally to any future common stock or preferred stock that we may offer, we will describe the particular terms of any class or series of these securities in more detail in the applicable prospectus supplement. For the complete terms of our common stock and preferred stock, please refer to our articles of incorporation and our amended and restated bylaws that are incorporated by reference into the registration statement of which this prospectus is a part or may be incorporated by reference in this prospectus or any applicable prospectus supplement. The terms of these securities may also be affected by the Colorado Business Corporation Act. The summary below and that contained in any applicable prospectus supplement or any related free writing prospectus are qualified in their entirety by reference to our articles of incorporation and our amended and restated bylaws.

Common Stock

We are currently authorized to issue 30,000,000 shares of Common Stock, and as of October 1, 2012, (i) 12,331,499 shares of Common Stock were issued and outstanding, (ii) 750,000 shares were reserved for issuance under our 1998 Stock Option Plan, of which 185,586 shares remain unissued; (ii) 300,000 shares were reserved for issuance under the our 2009 Restricted Stock/Unit Plan, of which 155,845 shares remain unissued, and (iii) 45,000 shares were reserved for issuance upon exercise of a Non-Statutory Stock Option Agreement dated August 24, 2005 granted to one of our executive officers.

Voting Rights

Each share of Common Stock entitles the holder thereof to one vote on each matter for which shareholders are entitled to vote. A majority of the outstanding shares of our Common Stock of the Company entitled to vote at meetings of shareholders, present in person or by proxy, constitute a quorum at any meeting of shareholders. Matters are generally decided by the affirmative vote of a majority of the shares of our Common Stock present in person or by proxy and entitled to vote. The Board of Directors is elected by plurality and cumulative voting is not allowed. Thus, at each election of directors, that number of candidates equaling the number of directors to be elected, having the highest number of votes cast in favor of their election, shall be elected to the Board of Directors.

Dividends

Holders of Common Stock are entitled to dividends out of funds legally available for such dividends when, if and as declared by the Board of Directors.

-6-

Liquidation

In event of the voluntary or involuntary liquidation, dissolution, distribution of assets or other winding up, holders of our common stock have the right to receive ratably all of the assets remaining after payment of liabilities and liquidation preferences of any preferred stock then outstanding.

Other Matters

Shares of Common Stock are not liable to assessment or further call. Our Common Stock has no preemptive, conversion or other subscription rights. There are no redemption or sinking fund provisions applicable to our Common Stock. All outstanding shares of Common Stock are validly issued, fully paid and non-assessable.

Preferred Stock

We are authorized to issue 5,000,000 shares of preferred stock, none of which are issued and outstanding as of the date of this prospectus. Our board of directors is authorized to classify or reclassify any unissued portion of our authorized shares of preferred stock to provide for the issuance of shares of other classes or series, including preferred stock in one or more series. We may issue preferred stock from time to time in one or more class or series, with the exact terms of each class or series established by our board of directors. Our board of directors may issue preferred stock with voting and other rights that could adversely affect the voting power of the holders of our common stock without seeking shareholder approval. Additionally, the issuance of preferred stock may have the effect of decreasing the market price of the common stock and may adversely affect the voting power of holders of common stock and reduce the likelihood that common shareholders will receive dividend payments and payments upon liquidation.

The rights, preferences, privileges and restrictions of the preferred stock of each series will be fixed by the certificate of designation relating to each series. We will incorporate by reference into the registration statement of which this prospectus is a part the form of any certificate of designation that describes the terms of the series of preferred stock we are offering before the issuance of the related series of preferred stock. The applicable prospectus supplement will specify the terms of the series of preferred stock we are offering, including, but not limited to:

•

the distinctive designation and the maximum number of shares in the series;

•

the number of shares we are offering and purchase price per share;

•

the liquidation preference, if any;

•

the terms on which dividends, if any, will be paid;

•

the voting rights, if any, on the shares of the series;

•

the terms and conditions, if any, on which the shares of the series shall be convertible into, or exchangeable for, shares of any other class or classes of capital stock;

•

the terms on which the shares may be redeemed, if at all;

•

any listing of the preferred stock on any securities exchange or market;

-7-

•

a discussion of any material or special United States federal income tax considerations applicable to the preferred stock; and

•

any or all other preferences, rights, restrictions, including restrictions on transferability, and qualifications of shares of the series

The issuance of preferred stock may delay, deter or prevent a change in control.

The prospectus supplement relating to a preferred stock offering will contain a description of the specific terms of that series as fixed by our Board of Directors.

Anti-Takeover Effects of Provisions of our Charter Documents and Colorado Law

The following is a summary of certain provisions of Colorado law, our amended articles of incorporation and bylaws. This summary does not purport to be complete and is qualified in its entirety by reference to the corporate law of Colorado and our amended articles of incorporation and bylaws.

Size of Board. Our Bylaws provide that the size of the Board of Directors may not be changed except (i) by a resolution adopted by at least 80% of the votes entitled to be cast by each shareholder voting group entitled to vote thereon, or (ii) by unanimous consent of the Board of Directors. This provision of the Bylaws may not be changed except upon approval by at least 80% of the votes entitled to be cast by each voting group entitled to vote thereon.

Filling Vacancies on Board. Except with respect to a vacancy on the Board of Directors due to the removal of the Director, any vacancy on the Board may be filled by the affirmative vote of a majority of the shareholders or the Board of Directors. As a result of the ability of the Board to fill a vacancy, such new directors may not be up for shareholder election at the next annual meeting due to the staggered Board classification described below. The overall effect of these provisions may be to prevent a person or entity from immediately acquiring Board control.

Removal of Directors. Our Bylaws provide that any Director or the entire Board of Directors may be removed for cause only at a special meeting of the shareholders by the affirmative vote of at least 80% of the votes entitled to be cast by each voting group entitled to vote thereon at such meeting, if notice of the intention to act upon such matter shall have been given in the notice calling the meeting. The Bylaws also provide that vacancies arising as a result of the removal of directors by shareholder action may be filled at such meeting by the affirmative vote of at least 80% of the shares of the votes entitled to be cast by each voting group entitled to vote thereon. This provision of the Bylaws may not be changed except upon approval by at least 80% of the votes entitled to be cast by each voting group entitled to vote thereon.

Staggered Board of Directors. Our amended articles of incorporation provide that the Board of Directors is to be divided into three classes, each class to be as nearly equal in number as possible. At each annual meeting of shareholders, members of one of the classes, on a rotating basis, are elected for a three year term. The staggered Board provision cannot be amended or repealed by the directors and cannot be amended or repealed without the affirmative vote of the holders of at least 80% of the votes entitled to be cast in the election of directors.

-8-

Limited Ability for Shareholders to Call a Special Meeting. Our Bylaws only permit shareholders to call a special meeting if we receive one or more written demands for the meeting, stating the purpose or purposes of the meeting, signed and dated by holders of shares representing at least 10% of all votes entitled to be cast on any issue proposed to be considered at the meeting.

No cumulative voting. Cumulative voting in the election of directors is not allowed.

Indemnification. The amended articles provide that our directors and officers shall be indemnified and shall be advanced expenses incurred in defending a civil, criminal, administrative or investigative action, suit or proceeding arising out of their status as directors and officers to the fullest extent allowed by law.

-9-

DESCRIPTION OF DEPOSITARY SHARES

General

We may, at our option, elect to offer fractional shares or multiple shares of preferred stock, rather than whole individual shares of preferred stock. If we decide to do so, we will issue the preferred stock in the form of depositary shares. Each depository share will represent a fraction or multiple of a share of a particular series of preferred stock and will be evidenced by depositary receipts issued pursuant to the deposit agreement. Depositary receipts will be distributed to those persons purchasing the fractional or multiple shares of preferred stock in accordance with the terms of the prospectus supplement or other offering materials.

The shares of any series of preferred stock represented by depositary shares will be deposited under a deposit agreement between us and a bank or trust company selected by us having its principal office in the United States and having a combined capital and surplus of at least $50,000,000, as preferred stock depositary. Each owner of a depositary share will be entitled to all the rights and preferences of the underlying preferred stock, including dividend, voting, redemption, conversion and liquidation rights, in proportion to the applicable fraction of a share of preferred stock represented by the depositary share.

Dividends and Other Distributions

The preferred stock depositary will distribute all cash dividends or other cash distributions received in respect of the deposited preferred stock to the record holders of depositary shares relating to the underlying preferred stock in proportion to the number of the depositary shares owned by the holders.

The preferred stock depositary will distribute any property received by it other than cash to the record holders of depositary shares entitled to these distributions. If the preferred stock depositary determines that it is not feasible to make a distribution, it may, with our approval, sell the property and distribute the net proceeds from the sale to the holders of the depositary shares.

Conversion or Exchange of Preferred Stock

If a series of preferred stock represented by depositary shares is subject to conversion or exchange, the applicable prospectus supplement will describe the rights or obligations of each record holder of depositary receipts to convert or exchange the depositary shares.

Redemption of Preferred Stock

If we redeem a series of preferred stock represented by depositary shares, the depositary shares will be redeemed from the proceeds received by the preferred stock depositary resulting from the redemption, in whole or in part, of the applicable series of preferred stock. The depositary shares will be redeemed by the preferred stock depositary at a price per depositary share equal to the applicable fraction of the redemption price per share payable in respect of the shares of preferred stock so redeemed.

-10-

Whenever we redeem shares of preferred stock held by the preferred stock depositary, the preferred stock depositary will redeem as of the same date the number of depositary shares representing shares of preferred stock so redeemed. If fewer than all the depositary shares are to be redeemed, the depositary shares to be redeemed will be selected by the preferred stock depositary by lot or ratably or by any other equitable method as the preferred stock depositary decides.

Withdrawal of Preferred Stock

Unless the related depositary shares have previously been called for redemption, any holder of depositary shares may receive the number of whole shares of the related series of preferred stock and any money or other property represented by those depositary shares after surrendering the related depositary receipts at the corporate trust office of the preferred stock depositary. Holders of depositary shares making these withdrawals will be entitled to receive whole shares of preferred stock on the basis set forth in the prospectus supplement or other offering materials for that series of preferred stock.

However, holders of whole shares of preferred stock will not be entitled to deposit that preferred stock under the deposit agreement or to receive depositary shares for that preferred stock after withdrawal. If the depositary shares surrendered by the holder in connection with withdrawal exceed the number of depositary shares that represent the number of whole shares of preferred stock to be withdrawn, the preferred stock depositary will deliver to that holder at the same time new depositary receipts evidencing the excess number of depositary shares.

Voting Deposited Preferred Stock

When the preferred stock depositary receives notice of any meeting at which the holders of any series of deposited preferred stock are entitled to vote, the preferred stock depositary will mail the information contained in the notice to the record holders of the depositary shares relating to the applicable series of preferred stock. Each record holder of the depositary shares on the record date will be entitled to instruct the preferred stock depositary to vote the amount of the preferred stock represented by the holder’s depositary shares. To the extent possible, the preferred stock depositary will vote the amount of the series of preferred stock represented by depositary shares in accordance with the instructions it receives.

We will agree to take all reasonable actions that the preferred stock depositary determines are necessary to enable the preferred stock depositary to vote as instructed. The preferred stock depositary will vote all shares of any series of preferred stock held by it proportionately with instructions received if it does not receive specific instructions from the holders of depositary shares representing that series of preferred stock.

-11-

Amendment and Termination of the Deposit Agreement

The form of depositary receipt evidencing the depositary shares and any provision of the deposit agreement may at any time be amended by agreement between us and the preferred stock depositary. However, any amendment that imposes additional charges or materially and adversely alters the existing rights of the holders of depositary shares will not be effective unless the amendment has been approved by the holders of at least a majority of the affected depositary shares then outstanding. Holders who retain their depositary shares after the amendment becomes effective will be deemed to agree to the amendment and will be bound by the amended deposit agreement. The deposit agreement automatically terminates if:

•

all outstanding depositary shares have been redeemed;

•

each share of preferred stock has been converted into or exchanged for common stock; or

•

a final distribution in respect of the preferred stock has been made to the holders of depositary shares in connection with any liquidation, dissolution or winding up of our company.

We may terminate the deposit agreement at any time and the preferred stock depositary will give notice of that termination to the record holders of all outstanding depositary receipts not less than 30 days prior to the termination date. In that event, the preferred stock depositary will deliver or make available for delivery to holders of depositary shares, upon surrender of the related depositary receipts, the number of whole or fractional shares of the related series of preferred stock as are represented by those depositary shares.

Charges of Preferred Stock Depositary; Taxes and Other Governmental Charges

No fees, charges and expenses of the preferred stock depositary or any agent of the preferred stock depositary or of any registrar will be payable by any person other than us, except for any taxes and other governmental charges and except as provided in the deposit agreement. If the preferred stock depositary incurs fees, charges or expenses for which it is not otherwise liable at the election of a holder of depositary shares or other person, that holder or other person will be liable for those fees, charges and expenses.

Resignation and Removal of Depositary

The preferred stock depositary may resign at any time by delivering to us notice of its intent to do so, and we may at any time remove the preferred stock depositary. Any resignation or removal will take effect upon the appointment of a successor preferred stock depositary and its acceptance of the appointment. A successor preferred stock depositary must be appointed within 60 days after delivery of the notice of resignation or removal and must be a bank or trust company having its principal office in the United States and having a combined capital and surplus of at least $50,000,000.

-12-

Miscellaneous

The preferred stock depositary will forward all reports and communications from us which are delivered to the preferred stock depositary and which we are required to furnish to the holders of the deposited preferred stock.

Neither we nor the preferred stock depositary will be liable if it is prevented or delayed by law or any circumstances beyond its control in performing its obligations under the deposit agreement. Our obligations and that of the preferred stock depositary under the deposit agreement will be limited to performance with honest intentions of our and their duties under the agreement and we and they will not be obligated to prosecute or defend any legal proceeding in respect of any depositary shares, depositary receipts or shares of preferred stock unless satisfactory indemnity is furnished. We and the preferred stock depositary may rely upon written advice of counsel or accountants, or upon information provided by holders of depositary shares or other persons believed to be competent and on documents believed to be genuine.

-13-

DESCRIPTION OF DEBT SECURITIES

General

The debt securities that we may issue may constitute debentures, notes, bonds or other evidences of indebtedness of Natural Gas Services Group, Inc., to be issued in one or more series, which may include senior debt securities, subordinated debt securities and senior subordinated debt securities. The particular terms of any series of debt securities we may offer, including the extent to which the general terms set forth below may be applicable to a particular series, will be described in a prospectus supplement relating to such series.

Debt securities that we may issue may be issued under a senior indenture between us and a trustee, or a subordinated indenture between us and a trustee (collectively, the “indenture”). We have filed forms of the indentures as exhibits to the registration statement of which this prospectus is a part. If we enter into any revised indenture or indenture supplement, we will file a copy of that supplement with the Securities and Exchange Commission.

The following description is a summary of the material provisions of the indenture. It does not restate the indenture in its entirety. The indenture is governed by the Trust Indenture Act of 1939. The terms of the debt securities include those stated in the indenture and those made part of the indenture by reference to the Trust Indenture Act. We urge you to read the indenture because it, and not this description, defines your rights as a holder of the debt securities.

The indenture contains no covenant or provision which affords debt holders protection in the event of a highly leveraged transaction.

Information You Will Find in the Prospectus Supplement

The indenture provides that we may issue debt securities from time to time in one or more series by resolution of our board of directors or by means of a supplemental indenture, and that we may denominate the debt securities and make them payable in foreign currencies. The indenture does not limit the aggregate principal amount of debt securities that can be issued thereunder. The prospectus supplement for a series of debt securities will provide information relating to the terms of the series of debt securities being offered, which may include:

•

the title and denominations of the debt securities of the series;

•

any limit on the aggregate principal amount of the debt securities of the series;

•

the date or dates on which the principal and premium, if any, with respect to the debt securities of the series are payable or the method of determination thereof;

•

the rate or rates, which may be fixed or variable, at which the debt securities of the series shall bear interest, if any, or the method of calculating and/or resetting such rate or rates of interest;

•

the dates from which such interest shall accrue or the method by which such dates shall be determined and the basis upon which interest shall be calculated;

•

the interest payment dates for the series of debt securities or the method by which such dates will be determined, the terms of any deferral of interest and any right of ours to extend the interest payments periods;

-14-

•

the place or places where the principal and interest on the series of debt securities will be payable;

•

the terms and conditions upon which debt securities of the series may be redeemed, in whole or in part, at our option or otherwise;

•

our obligation, if any, to redeem, purchase, or repay debt securities of the series pursuant to any sinking fund or other specified event or at the option of the holders and the terms of any such redemption, purchase, or repayment;

•

the terms, if any, upon which the debt securities of the series may be convertible into or exchanged for other securities, including, among other things, the initial conversion or exchange price or rate and the conversion or exchange period;

•

if the amount of principal, premium, if any, or interest with respect to the debt securities of the series may be determined with reference to an index or formula, the manner in which such amounts will be determined;

•

if any payments on the debt securities of the series are to be made in a currency or currencies (or by reference to an index or formula) other than that in which such securities are denominated or designated to be payable, the currency or currencies (or index or formula) in which such payments are to be made and the terms and conditions of such payments;

•

any changes or additions to the provisions of the indenture dealing with defeasance, including any additional covenants that may be subject to our covenant defeasance option;

•

the currency or currencies in which payment of the principal and premium, if any, and interest with respect to debt securities of the series will be payable, or in which the debt securities of the series shall be denominated, and the particular provisions applicable thereto in accordance with the indenture;

•

the portion of the principal amount of debt securities of the series which will be payable upon declaration of acceleration or provable in bankruptcy or the method by which such portion or amount shall be determined;

•

whether the debt securities of the series will be secured or guaranteed and, if so, on what terms;

•

any addition to or change in the events of default with respect to the debt securities of the series;

•

the identity of any trustees, authenticating or paying agents, transfer agents or registrars;

•

the applicability of, and any addition to or change in, the covenants currently set forth in the indenture;

•

the subordination, if any, of the debt securities of the series and terms of the subordination;

•

whether securities of the series shall be issuable as registered securities or bearer securities (with or without interest coupons), and any restrictions applicable to the offering, sale or delivery of such bearer securities and the terms upon which such bearer securities of a series may be exchanged for registered securities, and vice versa; and

•

any other terms of the debt securities of the series.

-15-

Holders of debt securities may present debt securities for exchange in the manner, at the places, and subject to the restrictions set forth in the debt securities, the indenture, and the prospectus supplement. We will provide these services without charge, other than any tax or other governmental charge payable in connection therewith, but subject to the limitations provided in the indenture, any board resolution establishing such debt securities and any applicable indenture supplement. Debt securities in bearer form and the coupons, if any, appertaining thereto will be transferable by delivery.

Senior Debt

We may issue senior debt securities under the indenture and any coupons that will constitute part of our senior debt. Unless otherwise set forth in the applicable indenture supplement or in any board resolution establishing such debt securities and described in a prospectus supplement, the senior debt securities may be senior unsecured obligations, ranking equally with all of our existing and future senior unsecured debt. The senior debt securities will be senior to all of our subordinated debt and junior to any secured debt we may incur as to the assets securing such debt.

Subordinated Debt

We may issue subordinated debt securities under the indenture and any coupons that will constitute part of such subordinated debt. These subordinated debt securities will be subordinate and junior in right of payment, to the extent and in the manner set forth in the indenture and any applicable indenture supplement, to all of our senior indebtedness.

If this prospectus is being delivered in connection with a series of subordinated debt securities, the accompanying prospectus supplement or the information incorporated by reference will set forth the approximate amount of senior indebtedness, if any, outstanding as of the end of our most recent fiscal quarter.

Senior Subordinated Debt

We may issue senior subordinated debt securities under the indenture and any coupons that will constitute part of our senior subordinated debt. These senior subordinated debt securities will be, to the extent and in the manner set forth in the indenture, subordinate and junior in right of payment to all of our “senior indebtedness” and senior to our other subordinated debt.

Interest Rate

Debt securities that bear interest will do so at a fixed rate or a floating rate. We may sell, at a discount below the stated principal amount, any debt securities which bear no interest or which bear interest at a rate that at the time of issuance is below the prevailing market rate. The relevant prospectus supplement will describe the special United States federal income tax considerations applicable to:

•

any discounted debt securities; and

•

any debt securities issued at par which are treated as having been issued at a discount for United States federal income tax purposes.

-16-

Registered Global Securities

We may issue registered debt securities of a series in the form of one or more fully registered global securities. We will deposit the registered global security with a depositary or with a nominee for a depositary identified in the prospectus supplement relating to such series. The global security or global securities will represent and will be in a denomination or aggregate denominations equal to the portion of the aggregate principal amount of outstanding registered debt securities of the series to be represented by the registered global security or securities. Unless it is exchanged in whole or in part for debt securities in definitive registered form, a registered global security may not be transferred, except as a whole in three cases:

•

the depositary for the registered global security to a nominee of the depositary;

•

by a nominee of the depositary to the depositary or another nominee of the depositary; and

•

by the depositary or any nominee to a successor of the depositary or a nominee of the successor.

The prospectus supplement relating to a series of debt securities will describe the specific terms of the depositary arrangement concerning any portion of that series of debt securities to be represented by a registered global security. We anticipate that the following provisions will generally apply to all depositary arrangements.

Upon the issuance of a registered global security, the depositary will credit, on its book-entry registration and transfer system, the principal amounts of the debt securities represented by the registered global security to the accounts of persons that have accounts with the depositary. These persons are referred to as “participants.” Any underwriters, agents or debtors participating in the distribution of debt securities represented by the registered global security will designate the accounts to be credited. Only participants or persons that hold interests through participants will be able to beneficially own interests in a registered global security. The depositary for a global security will maintain records of beneficial ownership interests in a registered global security for participants. Participants or persons that hold through participants will maintain records of beneficial ownership interests in a global security for persons other than participants. These records will be the only means to transfer beneficial ownership in a registered global security.

The laws of some states may require that specified purchasers of securities take physical delivery of the securities in definitive form. These laws may limit the ability of those persons to own, transfer or pledge beneficial interests in global securities.

-17-

So long as the depositary, or its nominee, is the registered owner of a registered global security, the depositary or its nominee will be considered the sole owner or holder of the debt securities represented by the registered global security for all purposes under the indenture. Except as set forth below, owners of beneficial interests in a registered global security:

•

may not have the debt securities represented by a registered global security registered in their names;

•

will not receive or be entitled to receive physical delivery of debt securities represented by a registered global security in definitive form; and

•

will not be considered the owners or holders of debt securities represented by a registered global security under the indenture.

Accordingly, each person owning a beneficial interest in a registered global security must rely on the procedures of the depositary for the registered global security and, if the person is not a participant, on the procedures of the participant through which the person owns its interests, to exercise any rights of a holder under the indenture applicable to the registered global security.

We understand that, under existing industry practices, if we request any action of holders, or if an owner of a beneficial interest in a registered global security desires to give or take any action which a holder is entitled to give or take under the indenture, the depositary for the registered global security would authorize the participants holding the relevant beneficial interests to give or take the action, and the participants would authorize beneficial owners owning through the participants to give or take the action or would otherwise act upon the instructions of beneficial owners holding through them.

Payment of Interest on and Principal of Registered Global Securities

We will make principal, premium, if any, and interest payments on debt securities represented by a registered global security registered in the name of a depositary or its nominee to the depositary or its nominee as the registered owner of the registered global security. None of Natural Gas Services Group, the trustee, or any paying agent for debt securities represented by a registered global security will have any responsibility or liability for:

•

any aspect of the records relating to, or payments made on account of, beneficial ownership interests in such registered global security;

•

maintaining, supervising, or reviewing any records relating to beneficial ownership interests;

•

the payments to beneficial owners of the global security of amounts paid to the depositary or its nominee; or

•

any other matter relating to the actions and practices of the depositary, its nominee or any of its participants.

We expect that the depositary, upon receipt of any payment of principal, premium or interest in respect of the global security, will immediately credit participants’ accounts with payments in amounts proportionate to their beneficial interests in the principal amount of a registered global security as shown on the depositary’s records. We also expect that payments by participants to owners of beneficial interests in a registered global security held through participants will be governed by standing instructions and customary practices. This is currently the case with the securities held for the accounts of customers registered in “street name.” Such payments will be the responsibility of participants.

-18-

Exchange of Registered Global Securities

We may issue debt securities in definitive form in exchange for the registered global security if both of the following occur:

•

the depositary for any debt securities represented by a registered global security is at any time unwilling or unable to continue as depositary or ceases to be a clearing agency registered under the Securities Exchange Act of 1934; and

•

we do not appoint a successor depositary within 90 days.

In addition, we may, at any time, determine not to have any of the debt securities of a series represented by one or more registered global securities. In this event, we will issue debt securities of that series in definitive form in exchange for all of the registered global security or securities representing those debt securities.

Our Covenants

The indenture includes covenants by us, including among other things that we will make all payments of principal and interest at the times and places required. The board resolution or supplemental indenture establishing each series of debt securities may contain additional covenants, including covenants which could restrict our right to incur additional indebtedness or liens and to take certain actions with respect to our businesses and assets.

Events of Default

Unless otherwise indicated in the applicable prospectus supplement, the following will be events of default under the indenture with respect to each series of debt securities issued under the indenture:

•

failure to pay when due any interest on any debt security of that series that continues for 30 days;

•

failure to pay when due the principal of, or premium, if any, on, any debt security of that series;

•

default in the payment of any sinking fund installment with respect to any debt security of that series when due and payable.

•

failure to perform any other covenant or agreement of ours under the indenture or the supplemental indenture with respect to that series or the debt securities of that series, continued for 90 days after written notice to us by the trustee or holders of at least 25% in aggregate principal amount of the outstanding debt securities of the series to which the covenant or agreement relates;

•

certain events of bankruptcy, insolvency or similar proceedings affecting us and our subsidiaries; and

-19-

•

any other event of default specified in any supplemental indenture under which such series of debt securities is issued.

Except as to certain events of bankruptcy, insolvency or similar proceedings affecting us and except as provided in the applicable prospectus supplement, if any event of default shall occur and be continuing with respect to any series of debt securities under the indenture, either the trustee or the holders of at least 25% in aggregate principal amount of outstanding debt securities of such series may accelerate the maturity of all debt securities of such series. Upon certain events of bankruptcy, insolvency or similar proceedings affecting us, the principal, premium, if any, and interest on all debt securities of each series shall be immediately due and payable.

After any such acceleration, but before a judgment or decree based on acceleration has been obtained by the trustee, the holders of a majority in aggregate principal amount of each affected series of debt securities may waive all defaults with respect to such series and rescind and annul such acceleration if all events of default, other than the non-payment of accelerated principal, have been cured, waived or otherwise remedied.

No holder of any debt securities will have any right to institute any proceeding with respect to the indenture or for any remedy under the indenture, unless such holder shall have previously given to the trustee written notice of a continuing event of default and the holders of at least 25% in aggregate principal amount of the outstanding debt securities of the relevant series shall have made written request and offered indemnity satisfactory to the trustee to institute such proceeding as trustee, and the trustee shall not have received from the holders of a majority in aggregate principal amount of the outstanding debt securities of such series a direction inconsistent with such request and shall have failed to institute such proceeding within 60 days. However, such limitations do not apply to a suit instituted by a holder of a debt security for enforcement of payment of the principal of and premium, if any, or interest on such debt security on or after the respective due dates expressed in such debt security.

Supplemental Indentures

We and the trustee may, at any time and from time to time, without prior notice to or consent of any holders of debt securities after issuance of such debt securities, enter into one or more supplemental indentures to, among other things:

•

add guarantees to or secure any series of debt securities;

•

add any additional Events of Default;

•

provide for the succession of another person pursuant to the provisions of the indenture relating to consolidations, mergers and sales of assets and the assumption by such successor of our covenants, agreements, and obligations, or to otherwise comply with the provisions of the indenture relating to consolidations, mergers, and sales of assets;

•

surrender any right or power conferred upon us under the indenture or to add to our covenants further covenants, restrictions, conditions or provisions for the protection of the holders of all or any series of debt securities;

-20-

•

cure any ambiguity or to correct or supplement any provision contained in the indenture, in any supplemental indenture or in any debt securities that may be defective or inconsistent with any other provision contained therein, so long as any such action does not adversely affect the interests of the holders of debt securities of any series in any material respect;

•

add or change or eliminate any of the provisions of the indenture to extent as shall be necessary to permit or facilitate the issuance of debt securities in bearer form, registrable or not registrable as to principal, and with or without interest coupons;

•

add to or change any of the provisions of the indenture to permit the defeasance and discharge of any series of debt securities pursuant to the indenture;

•

change, or eliminate any of the provisions of the indenture provided that any such change or elimination shall become effective only when there are no debt securities outstanding of any series created prior to the execution of such supplemental indenture

•

evidence and provide for the acceptance of appointment by a successor or separate trustee; and

•

establish the form or terms of debt securities of any series and to make any change that does not adversely affect the interests of the holders of debt securities.

With the consent of the holders of at least a majority in principal amount of debt securities of each series affected by such supplemental indenture (each series voting as one class), we and the trustee may enter into one or more supplemental indentures for the purpose of adding any provisions to or changing in any manner or eliminating any of the provisions of the indenture or modifying in any manner the rights of the holders of debt securities of each such series.

Notwithstanding our rights and the rights of the trustee to enter into one or more supplemental indentures with the consent of the holders of debt securities of the affected series as described above, no such supplemental indenture to be entered into after issuance of the debt securities shall, without the consent of the holder of each outstanding debt security of the affected series, among other things:

•

change the final maturity of the principal of, or any installment of interest on, any debt securities;

•

reduce the principal amount of any debt securities or the rate of interest on any debt securities;

•

change the currency in which any debt securities are payable;

•

release any security interest that may have been granted with respect to such debt securities;

•

impair the right of the holders to conduct a proceeding for any remedy available to the trustee;

•

reduce the percentage in principal amount of any series of debt securities whose holders must consent to an amendment or supplemental indenture;

•

modify the ranking or priority of the securities;

•

reduce any premium payable upon the redemption of any debt securities or change the time at which any debt security may be redeemed; or

-21-

•

make any change that adversely affects the relative rights of holders of subordinated debt securities with respect to senior debt securities.

Satisfaction and Discharge of the Indenture; Defeasance

Except to the extent set forth in a supplemental indenture with respect to any series of debt securities, we, at our election, may discharge the indenture and the indenture shall generally cease to be of any further effect with respect to that series of debt securities if (a) we have delivered to the trustee for cancellation all debt securities of that series (with certain limited exceptions) or (b) all debt securities of that series not previously delivered to the trustee for cancellation shall have become due and payable, or are by their terms to become due and payable within one year or are to be called for redemption within one year, and we have deposited with the trustee the entire amount sufficient to pay at maturity or upon redemption all such debt securities.

In addition, we have a “legal defeasance option” (pursuant to which we may terminate, with respect to the debt securities of a particular series, all of our obligations under such debt securities and the indenture with respect to such debt securities) and a “covenant defeasance option” (pursuant to which we may terminate, with respect to the debt securities of a particular series, our obligations with respect to such debt securities under certain specified covenants contained in the indenture). If we exercise our legal defeasance option with respect to a series of debt securities, payment of such debt securities may not be accelerated because of an event of default. If we exercise our covenant defeasance option with respect to a series of debt securities, payment of such debt securities may not be accelerated because of an event of default related to the specified covenants.

We may exercise our legal defeasance option or our covenant defeasance option with respect to the debt securities of a series only if we irrevocably deposit in trust with the trustee cash or U.S. government obligations (as defined in the indenture) for the payment of principal, premium, if any, and interest with respect to such debt securities to maturity or redemption, as the case may be. In addition, to exercise either of our defeasance options, we must comply with certain other conditions, including the delivery to the trustee of an opinion of counsel to the effect that the holders of debt securities of such series will not recognize income, gain or loss for Federal income tax purposes as a result of such defeasance and will be subject to Federal income tax on the same amounts, in the same manner and at the same times as would have been the case if such defeasance had not occurred (and, in the case of legal defeasance only, such opinion of counsel must be based on a ruling from the Internal Revenue Service or other change in applicable Federal income tax law).

The trustee will hold in trust the cash or U.S. government obligations deposited with it as described above and will apply the deposited cash and the proceeds from deposited U.S. government obligations to the payment of principal, premium, if any, and interest with respect to the debt securities of the defeased series. In the case of subordinated debt securities, the money and U.S. government obligations held in trust will not be subject to the subordination provisions of the indenture.

-22-

Mergers, Consolidations and Certain Sales of Assets

Under the proposed form of indenture, we may not (1) consolidate with or merge into any other person or entity or permit any other person or entity to consolidate with or merge into us in a transaction in which we are not the surviving entity, or (2) transfer, lease or dispose of all or substantially all of our assets to any other person or entity unless:

•

the resulting, surviving or transferee entity shall be a corporation organized and existing under the laws of the United States or any state thereof and such resulting, surviving or transferee entity shall expressly assume, by supplemental indenture, all of our obligations under the debt securities and the indenture;

•

immediately after giving effect to such transaction (and treating any indebtedness which becomes an obligation of the resulting, surviving or transferee entity as a result of such transaction as having been incurred by such entity at the time of such transaction), no default or event of default would occur or be continuing; and

•

we shall have delivered to the trustee an officers’ certificate and an opinion of counsel, each stating that such consolidation, merger or transfer and such supplemental indenture (if any) comply with the indenture.

Governing Law

The indenture and the debt securities will be governed by the laws of the State of New York.

No Personal Liability of Directors, Officers, Employees and Shareholders

No director, officer, incorporator or shareholder of Natural Gas Services Group, as such, shall have any liability for any obligations of Natural Gas Services Group under the debt securities or the indenture or for any claim based on, in respect of, or by reason of, such obligations or their creation, solely by reason of his, her, or its status as director, officer, incorporator or shareholder of Natural Gas Services Group. By accepting a debt security, each holder waives and releases all such liability, but only such liability. The waiver and release are part of the consideration for issuance of the debt securities. Nevertheless, such waiver may not be effective to waive liabilities under the federal securities laws and it has been the view of the Securities and Exchange Commission that such a waiver is against public policy.

Conversion or Exchange Rights

Any debt securities issued under the indenture may be convertible into or exchangeable for shares of our equity securities. The terms and conditions of such conversion or exchange will be set forth in the applicable prospectus supplement. Such terms may include, among others, the following:

•

the conversion or exchange price;

•

the conversion or exchange period;

-23-

•

provisions regarding our ability or that of the holder to convert or exchange the debt securities;

•

events requiring adjustment to the conversion or exchange price; and

•

provisions affecting conversion or exchange in the event of our redemption of such debt securities.

Concerning the Trustee

The indenture provides that there may be more than one trustee with respect to one or more series of debt securities. If there are different trustees for different series of debt securities, each trustee will be a trustee of a trust under a supplemental indenture separate and apart from the trust administered by any other trustee under such indenture. Except as otherwise indicated in this prospectus or any prospectus supplement, any action permitted to be taken by a trustee may be taken by the trustee only with respect to the one or more series of debt securities for which it is the trustee under an indenture. Any trustee under the indenture or a supplemental indenture may resign or be removed with respect to one or more series of debt securities. All payments of principal of, premium, if any, and interest on, and all registration, transfer, exchange, authentication and delivery of (including authentication and delivery on original issuance of the debt securities), the debt securities of a series will be effected by the trustee with respect to such series at an office designated by the trustee.

The indenture contains limitations on the right of the trustee, should it become a creditor of Natural Gas Services Group, to obtain payment of claims in certain cases or to realize on certain property received in respect of any such claim as security or otherwise. If the trustee acquires an interest that conflicts with any duties with respect to the debt securities, the trustee is required to either resign or eliminate such conflicting interest to the extent and in the manner provided by the indenture.

Limitations on Issuance of Bearer Debt Securities

Debt securities in bearer form are subject to special U.S. tax requirements and may not be offered, sold, or delivered within the United States or its possessions or to a U.S. person, except in certain transactions permitted by U.S. tax regulations. Investors should consult the relevant prospectus supplement, in the event that bearer debt securities are issued for special procedures and restrictions that will apply to such an offering.

-24-

DESCRIPTION OF RIGHTS

We may issue rights to purchase debt securities, preferred stock, common stock or depositary shares. These rights may be issued independently or together with any other security offered hereby and may or may not be transferable by the shareholder receiving the rights in such offering. In connection with any offering of such rights, we may enter into a standby arrangement with one or more underwriters or other purchasers pursuant to which the underwriters or other purchasers may be required to purchase any securities remaining unsubscribed for after such offering.

Each series of rights will be issued under a separate rights agreement which we will enter into with a bank or trust company, as rights agent, all as set forth in the applicable prospectus supplement. The rights agent will act solely as our agent in connection with the certificates relating to the rights and will not assume any obligation or relationship of agency or trust with any holders of rights certificates or beneficial owners of rights. We will file the rights agreement and the rights certificates relating to each series of rights with the Securities and Exchange Commission, and incorporate them by reference as an exhibit to the registration statement of which this prospectus is a part on or before the time we issue a series of rights.

The applicable prospectus supplement will describe the specific terms of any offering of rights for which this prospectus is being delivered, including the following:

•

the date of determining the shareholders entitled to the rights distribution;

•

the number of rights issued or to be issued to each shareholder;

•

the exercise price payable for each share of debt securities, preferred stock, common stock or other securities upon the exercise of the rights;

•

the number and terms of the shares of debt securities, preferred stock, common stock or other securities which may be purchased per each right;

•

the extent to which the rights are transferable;

•

the date on which the holder’s ability to exercise the rights shall commence, and the date on which the rights shall expire;

•

the extent to which the rights may include an over-subscription privilege with respect to unsubscribed securities;

•

if applicable, the material terms of any standby underwriting or purchase arrangement entered into by us in connection with the offering of such rights; and

•

any other terms of the rights, including the terms, procedures, conditions and limitations relating to the exchange and exercise of the rights.

The description in the applicable prospectus supplement of any rights that we may offer will not necessarily be complete and will be qualified in its entirety by reference to the applicable rights certificate, which will be filed with the Securities and Exchange Commission.

-25-

DESCRIPTION OF UNITS

We may issue units consisting of one or more debt securities, shares of common stock or preferred stock, warrants or any combination of such securities. The prospectus supplement relating to units will describe the terms of any units we issue, including as applicable:

•

the designation and terms of the units and the securities included in the units;

•

any provision for the issuance, payment, settlement, transfer or exchange of the units;

•

the date, if any, on and after which the units may be transferable separately;

•

whether we will apply to have the units traded on a securities exchange or securities quotation system;

•

any material United States federal income tax consequences; and

•

how, for United States federal income tax purposes, the purchase price paid for the units is to be allocated among the component securities.

DESCRIPTION OF WARRANTS

We may issue warrants for the purchase of debt securities, common stock, preferred stock or other securities. Warrants may be issued independently or together with debt securities, common stock, preferred stock or other securities offered by any prospectus supplement and may be attached to or separate from any such offered securities. Series of warrants may be issued under a separate warrant agreement entered into between us and a bank or trust company, as warrant agent, all as will be set forth in the prospectus supplement relating to the particular issue of warrants. The warrant agent would act solely as our agent in connection with the warrants and would not assume any obligation or relationship of agency or trust for or with any holders of warrants or beneficial owners of warrants.

You should refer to the provisions of the warrant agreement that will be filed with the Securities and Exchange Commission in connection with the offering of warrants for the complete terms of the warrant agreement.

Prior to the exercise of any warrants, holders of such warrants will not have any rights of holders of the securities purchasable upon such exercise, including the right to receive payments of dividends, or the right to vote such underlying securities.

USE OF PROCEEDS

Unless the applicable prospectus supplement states otherwise, we expect to use the net proceeds of the sale of our securities for general corporate purposes, including, but not limited to, acquisitions of companies or assets, repayment of existing indebtedness and for working capital. As of the date of this prospectus, we have not identified as probable any specific material proposed uses of these proceeds. If, as of the date of any prospectus supplement, we have identified any such uses, we will describe them in the prospectus supplement. The amount of our

-26-

securities offered from time to time pursuant to this prospectus and any prospectus supplement, and the precise amounts and timing of the application of net proceeds from the sale of those securities, will depend upon our funding requirements. If we elect at the time of an issuance of our securities to make different or more specific use of proceeds than described in this prospectus, such use will be described in the prospectus supplement relating to those securities.

RATIO OF EARNINGS TO FIXED CHARGES

If we offer debt securities and/or preference equity securities under this prospectus, then we will, at that time, provide a ratio of earnings to fixed charges and/or ratio of combined fixed charges and preference dividends to earnings, respectively, in the applicable prospectus supplement for such offering.

PLAN OF DISTRIBUTION

We may sell the securities covered by this prospectus from time to time. Registration of the securities covered by this prospectus does not mean, however, that those securities will necessarily be offered or sold.

We may sell the securities separately or together:

•

through one or more underwriters or dealers in a public offering and sale by them;

•

directly to investors;

•

through agents; or

•

through a combination of any of these methods of sale.

We may sell the securities from time to time:

•

in one or more transactions at a fixed price or prices, which may be changed from time to time;

•

at market prices prevailing at the times of sale;

•

at prices related to such prevailing market prices; or

•

at negotiated prices.

We will describe the method of distribution of the securities and the terms of the offering in the prospectus supplement.

Any discounts or concessions allowed or re-allowed or paid to dealers may be changed from time to time.

If underwriters are used in the sale of any securities, the securities will be acquired by the underwriters for their own account and may be resold from time to time in one or more transactions described above. The securities may be either offered to the public through underwriting syndicates represented by managing underwriters, or directly by underwriters. Generally, the underwriters’ obligations to purchase the securities will be subject to conditions

-27-

precedent and the underwriters will be obligated to purchase all of the securities if they purchase any of the securities. We may use underwriters with whom we have a material relationship. We will describe in the prospectus supplement, naming the underwriter, the nature of any such relationship.

We may authorize underwriters, dealers or agents to solicit offers by certain purchasers to purchase the securities from us at the public offering price set forth in the prospectus supplement pursuant to delayed delivery contracts providing for payment and delivery on a specified date in the future. The contracts will be subject only to those conditions set forth in the prospectus supplement, and the prospectus supplement will set forth any commissions we pay for solicitation of these contracts.

We may enter into derivative transactions with third parties, or sell securities not covered by this prospectus to third parties in privately negotiated transactions. If the applicable prospectus supplement indicates, in connection with those derivatives, the third parties may sell securities covered by this prospectus and the applicable prospectus supplement, including in short sale transactions. If so, the third party may use securities pledged by us or borrowed from us or others to settle those sales or to close out any related open borrowings of stock, and may use securities received from us in settlement of those derivatives to close out any related open borrowings of stock. The third party in such sale transactions will be an underwriter and will be identified in the applicable prospectus supplement or in a post-effective amendment.

Underwriters, dealers and agents may be entitled to indemnification by us against certain civil liabilities, including liabilities under the Securities Act, or to contribution with respect to payments made by the underwriters, dealers or agents, under agreements between us and the underwriters, dealers and agents.

We may grant underwriters who participate in the distribution of securities an option to purchase additional securities to cover over-allotments, if any, in connection with the distribution.

Underwriters, dealers or agents may receive compensation in the form of discounts, concessions or commissions from us or our purchasers, as their agents in connection with the sale of securities. These underwriters, dealers or agents may be considered to be underwriters under the Securities Act of 1933. As a result, discounts, commissions or profits on resale received by the underwriters, dealers or agents may be treated as underwriting discounts and commissions. The prospectus supplement will identify any such underwriter, dealer or agent and describe any compensation received by them from us. Any initial public offering price and any discounts or concessions allowed or re-allowed or paid to dealers may be changed from time to time.

Unless otherwise specified in the related prospectus supplement, all securities we offer, other than common stock, will be new issues of securities with no established trading market. Any underwriters may make a market in these securities, but will not be obligated to do so and may discontinue any market making at any time without notice. Any common stock sold pursuant to a prospectus supplement will be listed for trading on the New York Stock Exchange

-28-

or other principal market for our common stock. We may apply to list any series of debt securities, preferred stock, depositary shares, rights, units or warrants on an exchange, but we are not obligated to do so. Therefore, there may not be liquidity or a trading market for any series of securities.

Any underwriter may engage in over-allotment transactions, stabilizing transactions, short-covering transactions and penalty bids in accordance with Regulation M under the Securities Exchange Act of 1934. Over-allotment involves sales in excess of the offering size, which create a short position. Stabilizing transactions permit bids to purchase the underlying security so long as the stabilizing bids do not exceed a specified maximum. Short covering transactions involve purchases of the securities in the open market after the distribution is completed to cover short positions. Penalty bids permit the underwriters to reclaim a selling concession from a dealer when the securities originally sold by the dealer are purchased in a covering transaction to cover short positions. Those activities may cause the price of the securities to be higher than it would otherwise be. If commenced, the underwriters may discontinue any of the activities at any time. We make no representation or prediction as to the direction or magnitude of any effect that such transactions may have on the price of the securities. For a description of these activities, see the information under the heading “Underwriting” or “Plan of Distribution” in the applicable prospectus supplement.

Underwriters, broker-dealers or agents who may become involved in the sale of the common stock may engage in transactions with and perform other services for us in the ordinary course of their business for which they receive compensation.

LEGAL MATTERS

Unless otherwise indicated in the applicable prospectus supplement, Jones & Keller, P.C., Denver, Colorado will provide opinions regarding the authorization and validity of the securities. Jones & Keller, P.C. may also provide opinions regarding certain other matters. Any underwriters will also be advised about legal matters by their own counsel, which will be named in the prospectus supplement.

EXPERTS

The financial statements as of December 31, 2011 and 2010 and for each of the two years in the period ended December 31, 2011 and management’s assessment of the effectiveness of internal control over financial reporting as of December 31, 2011 incorporated by reference in this Prospectus and in the Registration Statement have been so incorporated in reliance on the reports of BDO USA, LLP, an independent registered public accounting firm, given upon the authority of such firm as experts in auditing and accounting.

The financial statements for the year ended December 31, 2009 incorporated by reference into this Prospectus and in the Registration Statement by reference from our Annual Report on Form 10-K have been audited by Hein & Associates LLP, our former independent registered public accounting firm, given upon the authority of such firm as experts in auditing and accounting.

-29-

TRANSFER AGENT AND REGISTRAR

Our Transfer Agent and Registrar is Computershare Trust Company, Inc., 350 Indiana Street, Suite 800, Golden, Colorado 80401.

INCORPORATION OF CERTAIN INFORMATION BY REFERENCE

Where You Can Find More Information

We file annual, quarterly and current reports, proxy statements and other information with the Commission. You may read and copy any reports, statements or other information we file with the Commission at the Commission’s Public Reference Room at 100 F Street, N.E., Washington, D.C. 20549. Please call the Commission at 1-800-SEC-0330 for further information on the operation of the Public Reference Room. Our Commission filings are also available to the public from commercial document retrieval services and at the Internet site maintained by the Commission at www.sec.gov.

We have filed with the Commission a registration statement on Form S-3 relating to the securities covered by this prospectus and any prospectus supplement. This prospectus is a part of the registration statement and does not contain all the information in the registration statement. Whenever a reference is made in this prospectus or any prospectus supplement to a contract or other document, the reference is only a summary and you should refer to the exhibits that are a part of the registration statement for a copy of the contract or other document. You may review a copy of the registration statement at the Commission’s public reference room in Washington, D.C., as well as through the Commission’s Internet site.

The Commission allows us to “incorporate by reference” into this prospectus the information we file with it, which means that we can disclose important information to you by referring you to those documents. The information incorporated by reference is considered to be part of this prospectus, and information we file later with the Commission will automatically update and supersede such information. The following documents filed with the Commission are hereby incorporated by reference into this prospectus:

our Annual Report on Form 10-K for the Fiscal Year Ended December 31, 2011;

our Quarterly Report on Form 10-Q for the quarters ended March 31, 2012 and June 30, 2012;

our Current Reports on Form 8-K filed on January 9, 2012, March 8, 2012, May 10, 2012, June 15, 2012, August 7, 2012 and October 11, 2012;

the description of our Common Stock, par value $.01 per share, set forth in our Registration Statement on Form 8-A filed on July 17, 2002, including any amendment or report filed for the purpose of updating such description;

-30-

our Definitive Proxy Statement on Schedule 14A filed on April 27, 2012; and

all documents filed by us with the Commission pursuant to Sections 13(a), 13(c), 14 and 15(d) of the Securities Exchange Act of 1934, as amended, subsequent to the date of this Registration Statement shall be deemed to be incorporated herein by reference and to be a part of this Registration Statement from the date of the filing of such documents until such time as there shall have been filed a post-effective amendment that indicates that all securities offered hereby have been sold or that deregisters all securities remaining unsold at the time of such amendment.

Our Internet address is www.ngsgi.com. We make available free of charge, through the investor relations section of our website, Annual Reports on Form 10-K, Quarterly Reports on Form 10-Q and Current Reports on Form 8-K and amendments to those reports filed or furnished pursuant to Section 13(a) or 15(d) of the Securities Exchange Act of 1934 as soon as reasonably practicable after we electronically file such material with, or furnish it to, the securities and Exchange Commission. The information which appears on this web site is not part of this prospectus.

This prospectus is part of a registration statement that we filed with the Commission. Upon written or oral request, we will provide, without charge, to each person, including beneficial owners of our securities, to whom a copy of this prospectus is delivered, a copy of any or all of the information incorporated by reference in this prospectus (other than exhibits to such documents, unless the exhibits are specifically incorporated by reference in such documents). Your requests for copies should be directed to the Investor Relations, 508 West Wall Street, Suite 550, Midland, Texas 79701; telephone (432) 262-2700.

DISCLOSURE OF COMMISSION POSITION ON INDEMNIFICATION

FOR SECURITIES ACT LIABILITIES

Insofar as indemnification for liabilities arising under the Securities Act of 1933 may be permitted to directors, officers and controlling persons of registrant pursuant to the above, the registrant has been advised that in the opinion of the SEC such indemnification is against public policy as expressed in the Securities Act and is, therefore, unenforceable.

-31-

PART II

INFORMATION NOT REQUIRED IN PROSPECTUS

ITEM 14.

OTHER EXPENSES OF ISSUANCE AND DISTRIBUTION, ESTIMATED

The following is a statement of the estimated costs and expenses, other than underwriting compensation, incurred or expected to be incurred by us in connection with the issuance and distribution of an assumed amount of $150,000,000 of securities being registered pursuant to this registration statement. The assumed amount has been used to demonstrate the costs and expenses of an offering of the entire assumed amount of securities being registered and does not represent an estimate of the amount of securities that may be offered because such amount is unknown at this time. All of the amounts shown are estimates except for the SEC registration fee. The amounts also assume no listing of any additional class of securities on the New York Stock Exchange that would require the payment of an additional listing fee.


Securities and Exchange Commission Fee	$	20,460
Filing & Printing Expense	$	5,000	*
Legal Fees	$	6,500	*
Accountants’ Fees	$	3,500	*
Miscellaneous Fees and Expenses	$	1,540	*

Total	$	37,000	*

* Because an indeterminate amount of securities is covered by this Registration Statement, the expenses in connection with the issuance and distribution of the securities are not currently determinable. The expenses set forth above relate solely to the preparation and filing of this Registration Statement.

ITEM 15.

INDEMNIFICATION OF DIRECTORS AND OFFICERS

Section 7-109-102 of the Colorado Business Corporation Act permits a Colorado corporation to indemnify any director against liability if such person acted in good faith and, in the case of conduct in an official capacity with the corporation, that the director’s conduct was in the corporation’s best interests and, in all other cases, that the director’s conduct was at least not opposed to the best interests of the corporation or, with regard to criminal proceedings, the director had no reasonable cause to believe the director’s conduct was unlawful.

Section 7-109-103 of the Colorado Business Corporation Act provides that, unless limited by its articles of incorporation, a Colorado corporation shall indemnify a person who was wholly successful, on the merits or otherwise, in the defense of any proceeding to which the person was a party because the person is or was a director, against reasonable expenses incurred by him or her in connection with the proceeding.

II-1

Section 3 of Article IX of our articles of incorporation provides that we shall indemnify, to the maximum extent permitted by law in effect from time to time, any person who is or was a director, officer, agent, fiduciary or employee of ours against any claim, liability or expense arising against or incurred by such person made party to a proceeding because such person is or was a director, officer, agent, fiduciary or employee of ours or because such person is or was serving another entity as a director, officer, partner trustee, employee, fiduciary or agent at our request. We further have the authority to the maximum extent permitted by law to purchase and maintain insurance providing such indemnification.

Article VI of our bylaws provides for the indemnification of certain persons.

Insofar as indemnification for liabilities arising under the Securities Act of 1933 may be permitted to our directors, officers and controlling persons pursuant to the foregoing provisions, or otherwise, we have been advised that in the opinion of the Securities and Exchange Commission such indemnification is against public policy as expressed in the Securities Act of 1933 and is, therefore, unenforceable.

At present, there is no pending litigation or proceeding involving any of our directors, officers, employees or agents where indemnification will be required or permitted. Insofar as indemnification for liabilities arising under the 1933 Act may be permitted to our directors, officers and controlling persons pursuant to the foregoing provisions, or otherwise, we have been advised that in the opinion of the SEC, such indemnification is against public policy as expressed in the 1933 Act and is, therefore, unenforceable.

II-2

ITEM 16.

EXHIBITS


Exhibit No.		Description

1.1		Form of Underwriting Agreement†

3.1		Articles of Incorporation, as amended (Incorporated by reference to Exhibit 3.1 of Form 10-QSB filed and dated November 10, 2004)

3.2		Bylaws (Incorporated by reference to Exhibit 3.4 of the Registrant’s Registration Statement on Form SB-2, No. 333-88314)

4.1		Form of Senior Indenture (Incorporated by reference to Exhibit 4.1 of the Registrant’s Registration Statement on Form S-3, No. 333-161346, filed with the SEC on August 14, 2009)

4.2		Form of Senior Note†

4.3		Form of Subordinated Indenture (Incorporated by reference to Exhibit 4.1 of the Registrant’s Registration Statement on Form S-3, No. 333-161346, filed with the SEC on August 14, 2009)

4.4		Form of Subordinated Note†

4.5		Form of Deposit Agreement, including Form of Depositary Share†

4.6		Form of Warrant Agreement, including Form of Warrant Certificate†

4.7		Form of Unit Agreement†

4.8		Form of Preferred Stock Certificate†

4.9		Form of Certificate of Designation with respect to Preferred Stock†

4.10		Rights Agreement, including Form of Rights Certificate†

5.1		Opinion of Jones & Keller, P.C. regarding the legality of the common stock being registered*

23.1		Consent of BDO USA*

23.2		Consent of Hein & Associates LLP*

23.3		Consent of Jones & Keller, P.C. (included in Exhibit 5.1)

24.1		Power of Attorney (included on signature page hereof)

25.1		Statement of Eligibility on Form T-1 under the Trust Indenture Act of 1939, as amended (to be incorporated herein by reference from a subsequent filing in accordance with section 304(b)(2) of the Trust Indenture Act of 1939.)

*	Filed herewith.

†	If applicable, to be subsequently filed by amendment or as an exhibit to a Current Report on Form 8-K and incorporated herein by reference.

II-3

ITEM 17.

UNDERTAKINGS

The undersigned registrant hereby undertakes:

(1) To file, during any period in which offers or sales are being made, a post-effective amendment to this registration statement:

To include any prospectus required by Section 10(a)(3) of the Securities Act of 1933;

ii.

To reflect in the prospectus any facts or events arising after the effective date of the registration statement (or the most recent post-effective amendment thereof) which, individually or in the aggregate, represent a fundamental change in the information set forth in the registration statement. Notwithstanding the foregoing, any increase or decrease in volume of securities offered (if the total dollar value of securities offered would not exceed that which was registered) and any deviation from the low or high end of the estimated maximum offering range may be reflected in the form of prospectus filed with the Commission pursuant to Rule 424(b) if, in the aggregate, the changes in volume and price represent no more than a 20 percent change in the maximum aggregate offering price set forth in the “Calculation of Registration Fee” table in the effective registration statement; and

iii.

To include any material information with respect to the plan of distribution not previously disclosed in the registration statement or any material change to such information in the registration statement;

provided, however, that

(A)

the undertakings set forth in paragraphs (1)(i), (1)(ii) and (1)(iii) above do not apply if the registration statement is on Form S-8, and the information required to be included in a post-effective amendment by those paragraphs is contained in reports filed with or furnished to the Commission by the registrant pursuant to section 13 or section 15(d) of the Securities Exchange Act of 1934 that are incorporated by reference in the registration statement; and

(B)

the undertakings set forth in paragraphs (1)(i), (1)(ii) and (1)(iii) above do not apply if the registration statement is on Form S-3 or Form F-3 and the information required to be included in a post-effective amendment by those paragraphs is contained in reports filed with or furnished to the Commission by the registrant pursuant to Section 13 or Section 15(d) of the Securities Exchange Act of 1934 that are incorporated by reference in the registration statement or is contained in a form of prospectus filed pursuant to Rule 424(b) that is a part of the registration statement.

(C)

Provided further, however, that paragraphs (1)(i), (1)(ii) and (1)(iii) above do not apply if the registration statement is for an offering of asset-backed securities on Form S-1 or Form S-3, and the information required to be included in a post-effective amendment is provided pursuant to Item 1100(c) of Regulation AB.

II-4

(2) That, for the purpose of determining any liability under the Securities Act of 1933, each such post-effective amendment shall be deemed to be a new registration statement relating to the securities offered therein, and the offering of such securities at that time shall be deemed to be the initial bona fide offering thereof.

(3) To remove from registration by means of a post-effective amendment any of the securities being registered which remain unsold at the termination of the offering.

(4) That, for the purpose of determining liability under the Securities Act of 1933 to any purchaser:

Each prospectus filed by the registrant pursuant to Rule 424(b)(3) shall be deemed to be part of the registration statement as of the date the filed prospectus was deemed part of and included in the registration statement; and

ii.

Each prospectus required to be filed pursuant to Rule 424(b)(2), (b)(5), or (b)(7) as part of a registration statement in reliance on Rule 430B relating to an offering made pursuant to Rule 415(a)(1)(i), (vii), or (x) for the purpose of providing the information required by section 10(a) of the Securities Act of 1933 shall be deemed to be part of and included in the registration statement as of the earlier of the date such form of prospectus is first used after effectiveness or the date of the first contract of sale of securities in the offering described in the prospectus. As provided in Rule 430B, for liability purposes of the issuer and any person that is at that date an underwriter, such date shall be deemed to be a new effective date of the registration statement relating to the securities in the registration statement to which that prospectus relates, and the offering of such securities at that time shall be deemed to be the initial bona fide offering thereof. Provided, however, that no statement made in a registration statement or prospectus that is part of the registration statement or made in a document incorporated or deemed incorporated by reference into the registration statement or prospectus that is part of the registration statement will, as to a purchaser with a time of contract of sale prior to such effective date, supersede or modify any statement that was made in the registration statement or prospectus that was part of the registration statement or made in any such document immediately prior to such effective date.

(5) That, for the purpose of determining liability of the registrant under the Securities Act of 1933 to any purchaser in the initial distribution of the securities, the undersigned registrant undertakes that in a primary offering of securities of the undersigned registrant pursuant to this registration statement, regardless of the underwriting method used to sell the securities to the purchaser, if the securities are offered or sold to such purchaser by means of any of the following communications, the undersigned registrant will be a seller to the purchaser and will be considered to offer or sell such securities to such purchaser:

II-5

Any preliminary prospectus or prospectus of the undersigned registrant relating to the offering required to be filed pursuant to Rule 424;

ii.

Any free writing prospectus relating to the offering prepared by or on behalf of the undersigned registrant or used or referred to by the undersigned registrant;

iii.

The portion of any other free writing prospectus relating to the offering containing material information about the undersigned registrant or its securities provided by or on behalf of the undersigned registrant; and

iv.

Any other communication that is an offer in the offering made by the undersigned registrant to the purchaser.

The undersigned registrant hereby undertakes that, for purposes of determining any liability under the Securities Act of 1933, each filing of the registrant’s annual report pursuant to Section 13(a) or Section 15(d) of the Securities Exchange Act of 1934 (and, where applicable, each filing of an employee benefit plan’s annual report pursuant to Section 15(d) of the Securities Exchange Act of 1934) that is incorporated by reference in the registration statement shall be deemed to be a new registration statement relating to the securities offered therein, and the offering of such securities at that time shall be deemed to be the initial bona fide offering thereof.

The undersigned registrant hereby undertakes to deliver or cause to be delivered with the prospectus, to each person to whom the prospectus is sent or given, the latest annual report to security holders that is incorporated by reference in the prospectus and furnished pursuant to and meeting the requirements of Rule 14a-3 or Rule 14c-3 under the Securities Exchange Act of 1934; and, where interim financial information required to be presented by Article 3 of Regulation S-X are not set forth in the prospectus, to deliver, or cause to be delivered to each person to whom the prospectus is sent or given, the latest quarterly report that is specifically incorporated by reference in the prospectus to provide such interim financial information.

The undersigned registrant hereby undertakes that:

(1) For purposes of determining any liability under the Securities Act of 1933, the information omitted from the form of prospectus filed as part of this registration statement in reliance upon Rule 430A and contained in a form of prospectus filed by the registrant pursuant to Rule 424(b)(1) or (4) or 497(h) under the Securities Act of 1933 shall be deemed to be part of this registration statement as of the time it was declared effective.

(2) For the purpose of determining any liability under the Securities Act of 1933, each post-effective amendment that contains a form of prospectus shall be deemed to be a new registration statement relating to the securities offered therein, and the offering of such securities at that time shall be deemed to be the initial bona fide offering thereof.

Insofar as indemnification for liabilities arising under the Securities Act of 1933 may be permitted to directors, officers and controlling persons of the registrant pursuant to the foregoing provisions, or otherwise, the registrant has been advised that in the opinion of the Securities and Exchange Commission such indemnification is against public policy as expressed in the Act and is, therefore, unenforceable. In the event that a claim for indemnification against such liabilities

II-6

(other than the payment by the registrant of expenses incurred or paid by a director, officer or controlling person of the registrant in the successful defense of any action, suit or proceeding) is asserted by such director, officer or controlling person in connection with the securities being registered, the registrant will, unless in the opinion of its counsel the matter has been settled by controlling precedent, submit to a court of appropriate jurisdiction the question whether such indemnification by it is against public policy as expressed in the Act and will be governed by the final adjudication of such issue.

II-7

SIGNATURES

Pursuant to the requirements of the Securities Act of 1933, the Registrant certifies that it has reasonable grounds to believe that it meets all of the requirements for filing on Form S-3 and has duly caused this registration statement to be signed on its behalf by the undersigned, thereunto duly authorized in the City of Midland, State of Texas, on October 31, 2012.


NATURAL GAS SERVICES GROUP, INC.

By:		/s/ Stephen C. Taylor
		Stephen C. Taylor Chief Executive Officer



By:		/s/ G. Larry Lawrence
		G. Larry Lawrence Principal Accounting Officer

KNOW ALL MEN BY THESE PRESENTS, that the undersigned officers or directors of the registrant, by virtue of their signatures to this registration statement appearing below, hereby constitute and appoint Stephen C. Taylor and G. Larry Lawrence, attorneys-in-fact in their names, place, and stead to execute any and all amendments to this registration statement in the capacities set forth opposite their names and hereby ratify all that said attorneys-in-fact may do by virtue hereof.

Pursuant to the requirements of the Securities Act of 1933, this registration statement has been signed by the following persons in the capacities and on the date indicated.


Signature	Title	Date

/s/ Stephen C. Taylor Stephen C. Taylor	Director	October 31, 2012

/s/ David L. Bradshaw David L. Bradshaw	Director	October 31, 2012

/s/ John W. Chisholm John W. Chisholm	Director	October 31, 2012

II-8



/s/ Charles G. Curtis Charles G. Curtis	Director	October 31, 2012

/s/ William F. Hughes, Jr. William F. Hughes, Jr.	Director	October 31, 2012

/s/ Kenneth V. Huseman Kenneth V. Huseman	Director	October 31, 2012

II-9

EXHIBIT INDEX


Exhibit No.		Description

1.1		Form of Underwriting Agreement†

3.1		Articles of Incorporation, as amended (Incorporated by reference to Exhibit 3.1 of Form 10-QSB filed and dated November 10, 2004)

3.2		Bylaws (Incorporated by reference to Exhibit 3.4 of the Registrant’s Registration Statement on Form SB-2, No. 333-88314)

4.1		Form of Senior Indenture (Incorporated by reference to Exhibit 4.1 of the Registrant’s Registration Statement on Form S-3, No. 333-161346, filed with the SEC on August 14, 2009)

4.2		Form of Senior Note†

4.3		Form of Subordinated Indenture (Incorporated by reference to Exhibit 4.1 of the Registrant’s Registration Statement on Form S-3, No. 333-161346, filed with the SEC on August 14, 2009)

4.4		Form of Subordinated Note†

4.5		Form of Deposit Agreement, including Form of Depositary Share†

4.6		Form of Warrant Agreement, including Form of Warrant Certificate†

4.7		Form of Unit Agreement†

4.8		Form of Preferred Stock Certificate†

4.9		Form of Certificate of Designation with respect to Preferred Stock†

4.10		Rights Agreement, including Form of Rights Certificate†

5.1		Opinion of Jones & Keller, P.C. regarding the legality of the common stock being registered*

23.1		Consent of BDO USA*

23.2		Consent of Hein & Associates LLP*

23.3		Consent of Jones & Keller, P.C. (included in Exhibit 5.1)

24.1		Power of Attorney (included on signature page hereof)

25.1		Statement of Eligibility on Form T-1 under the Trust Indenture Act of 1939, as amended (to be incorporated herein by reference from a subsequent filing in accordance with section 304(b)(2) of the Trust Indenture Act of 1939.)

*	Filed herewith.

†	If applicable, to be subsequently filed by amendment or as an exhibit to a Current Report on Form 8-K and incorporated herein by reference.

II-10