As filed with the Securities and Exchange Commission on May 28, 2003.

                                        Registration no. 333-105405



                       SECURITIES AND EXCHANGE COMMISSION

                             Washington, D.C. 20549



                          PRE-EFFECTIVE AMENDMENT NO. 1
                                       TO

                                    FORM S-3
                             REGISTRATION STATEMENT
                                      UNDER
                           THE SECURITIES ACT OF 1933

                                  LABONE, INC.

             (Exact name of Registrant as specified in its charter)

Missouri                                               43-1039532
(State or other jurisdiction of                     (I.R.S. Employer
incorporation or organization)                      Identification Number)

                               10101 Renner Blvd.
                              Lenexa, Kansas 66219
                                 (913) 888-1770

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

                                Joseph C. Benage
             Executive Vice President, General Counsel and Secretary
                                  LabOne, Inc.
                               10101 Renner Blvd.
                              Lenexa, Kansas 66219
                                 (913) 888-1770

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


      APPROXIMATE DATE OF COMMENCEMENT OF PROPOSED SALE TO THE PUBLIC: From time
to time after the effective date of this Registration Statement.

      If the only securities being registered on this form are being offered
pursuant to dividend or interest reinvestment plan, 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 of
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, 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 delivery of the prospectus is expected to be made pursuant to Rule 434,
please check the following box. [ ]




        [Graphic omitted.]


      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 SECURITIES AND EXCHANGE COMMISSION, ACTING
PURSUANT TO SECTION 8(A), MAY DETERMINE.






THE INFORMATION IN THIS PROSPECTUS IS NOT COMPLETE AND MAY BE CHANGED. THE
SELLING STOCKHOLDERS MAY NOT SELL THESE SECURITIES UNTIL THE REGISTRATION
STATEMENT FILED WITH THE SECURITIES AND EXCHANGE COMMISSION IS EFFECTIVE. THIS
PROSPECTUS IS NOT AN OFFER TO SELL THESE SECURITIES, AND IT IS NOT SOLICITING AN
OFFER TO BUY THESE SECURITIES, IN ANY STATE WHERE THE OFFER OR SALE IS NOT
PERMITTED.



                    SUBJECT TO COMPLETION, DATED MAY 28, 2003


                                  LabOne, Inc.


                                 283,998 Shares

                                  Common Stock


      This prospectus relates to the offer and sale of up to 283,998 shares of
common stock of LabOne, Inc. by selling stockholders. We will not receive any of
the proceeds from the shares of our common stock sold by the selling
stockholders. The shares to be sold by the selling stockholders were obtained
upon exercise of warrants originally issued to the selling stockholders in
connection with an acquisition by us for which the selling stockholders provided
financing.

      Our common stock is traded on the Nasdaq National Market under the symbol
"LABS". The last reported sale price of the common stock on the Nasdaq National
Market on May 23, 2003 was $19.79 per share.

      The selling stockholders may sell shares pursuant to this prospectus in
the over-the-counter market, on the Nasdaq National Market or otherwise at
prices and on terms then prevailing or at prices related to the then current
market price (in each case as determined by the selling stockholders). Sales may
be made directly or through agents designated from time to time, or through
dealers or underwriters to be designated or in negotiated transactions.



           Investing in our common stock involves risks. See "Risk Factors"
beginning on page 4.

      Neither the Securities and Exchange Commission nor any state securities
commission has approved or disapproved of these securities or determined if this
prospectus is truthful or complete. Any representation to the contrary is a
criminal offense.




                The date of this prospectus is __________ , 2003






                                TABLE OF CONTENTS

                                                              Page
                                                              ----

Where You Can Find Additional Information........................1

Special Note Regarding Forward-Looking Statements................2

Summary..........................................................2

Risk Factors.....................................................3

Selling Stockholders.............................................6

Plan of Distribution.............................................8

Use of Proceeds.................................................10

Legal Matters...................................................10

Experts.........................................................10


      You should rely only on the information contained or incorporated by
reference in this prospectus. We have not authorized anyone to provide you with
information different from that contained in this prospectus. We are offering to
sell, and seeking offers to buy, shares of common stock 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 common stock. In this
prospectus, references to "LabOne", "we", "our" and "us" refer to LabOne, Inc.






                    WHERE YOU CAN FIND ADDITIONAL INFORMATION

      We have filed with the Securities and Exchange Commission a registration
statement on Form S-3 under the Securities Act with respect to the common stock
offered by this prospectus. We refer you to this registration statement for
further information about us and the shares of common stock offered hereby.

      We file annual, quarterly and special reports, proxy and information
statements and other information with the Securities and Exchange Commission
("SEC") (Commission File Number 0-16946). These filings contain important
information which does not appear in this prospectus. Our SEC filings are
available over the Internet at the SEC's website at HTTP://WWW.SEC.GOV. You may
also read and copy these filings at the SEC's public reference room at 450 Fifth
Street, N.W., Washington, D.C. 20549. You may obtain information on the
operation of the public reference room by calling the SEC at 1-800-SEC-0330, and
may obtain copies of our filings from the public reference room by calling (202)
942-8090.

      The SEC allows us to "incorporate by reference" information into this
prospectus, which means that we can disclose important information to you by
referring you to other documents which we have filed or will file with the SEC.
We are incorporating by reference into this prospectus the following documents
filed with the SEC:


     o    our Annual Report on Form 10-K for the fiscal year ended December 31,
          2002;


     o    our Quarterly Report on Form 10-Q for the quarter ended March 31,
          2003;

     o    the description of our Common Stock contained in the Form 8-A/A filed
          September 7, 1999 to our registration statement on Form 8-A under the
          Securities Exchange Act, including any amendment or report updating
          this description; and

     o    the description of preferred stock purchase rights set forth in the
          registration statement on Form 8-A dated February 11, 2000, filed by
          us with the SEC on February 14, 2000, including any amendment or
          report filed for the purpose of updating such description.

      All documents which we file with the SEC pursuant to Section 13(a), 13(c)
or 15(d) of the Securities Exchange Act after the date of this prospectus and
before the termination of this offering of common stock shall be deemed to be
incorporated by reference in this prospectus and to be a part of it from the
filing dates of such documents. Also, all such documents filed by us after the
date of the registration statement of which this prospectus forms a part and
prior to effectiveness of the registration statement shall be deemed to be
incorporated by reference in this prospectus and to be a part of it from the
filing dates of such documents. Certain statements in and portions of this
prospectus update and replace information in the above listed documents
incorporated by reference. Likewise, statements in or portions of a future
document incorporated by reference in this prospectus may update and replace
statements in and portions of this prospectus or the above listed documents.

      The following information contained in such documents is not incorporated
herein by reference: (a) information furnished under Items 9 and 12 of our
Current Reports on Form 8-K, (b) certifications accompanying or furnished in any
such documents pursuant to Title 18, Section 1350 of the United States Code and
(c) any other information in such documents which is not deemed to be filed with
the SEC under Section 18 of the Securities Exchange Act of 1934, as amended, or
otherwise subject to the liabilities of that section. We furnished information
under Item 9 of the Current Reports on Form 8-K filed by us with the SEC on
January 3, 2003, February 20, 2003, March 28, 2003 and May 13, 2003.

                                       1


      We shall provide you without charge, upon your written or oral request, a
copy of any of the documents incorporated by reference in this prospectus, other
than exhibits to such documents which are not specifically incorporated by
reference into such documents or this prospectus. Please direct your written or
telephone requests to Joseph C. Benage, Executive Vice President, General
Counsel and Secretary, LabOne, Inc., 10101 Renner Blvd., Lenexa, Kansas 66219
(telephone number (913) 888-1770)).

                SPECIAL NOTE REGARDING FORWARD-LOOKING STATEMENTS


      This prospectus may contain "forward-looking statements," including, but
not limited to: projections of revenues, income or loss, margins, capital
expenditures, cost savings and synergies, the payment or non-payment of
dividends and other financial items, statements of plans and objectives,
statements of future economic performance and statements of assumptions
underlying such statements, and statements of our intentions, hopes, beliefs,
expectations or predictions of the future. Forward-looking statements can often
be identified by the use of forward-looking terminology, such as "could,"
"should," "will," "will be," "intended," "continue," "believe," "may," "expect,"
"hope," "anticipate," "goal," "forecast," "plan," or "estimate" or variations
thereof or similar expressions. Forward-looking statements are not guarantees of
future performance or results. Forward-looking statements involve known and
unknown risks and uncertainties. Many factors could cause actual results to
differ materially from those that may be expressed or implied in such
forward-looking statements, including, but not limited to, the volume, pricing
and mix of services provided by us, intense competition, the loss of one or more
significant customers, general economic conditions and other factors detailed
from time to time in our reports and registration statements filed with the
SEC. The cautionary statements made in this prospectus apply to all
forward-looking statements wherever they appear in this prospectus.



                                     SUMMARY

      LabOne provides risk assessment services for the insurance
industry, laboratory testing services for the healthcare industry
and substance abuse testing services for employers and third
party administrators.  We and our wholly-owned subsidiaries
Osborn Group, Inc., Intellisys, Inc., Lab One Canada Inc.,
Systematic Business Services, Inc., ExamOne World Wide, Inc., and
Central Plains Laboratories, L.L.C., are hereinafter collectively
referred to as LabOne.

      Our risk assessment services comprise underwriting and claims support
services including teleunderwriting, specimen collection and paramedical
examinations, laboratory testing, telephone inspections, motor vehicle reports,
claims investigation services and medical information retrieval to the insurance
industry. The laboratory tests that we perform and data we gather are
specifically designed to assist an insurance company in objectively evaluating
the mortality and morbidity risks posed by policy applicants. The majority of
the testing is performed on specimens of individual life insurance policy
applicants, but also includes specimens of individuals applying for individual
and group medical and disability policies.

      Our clinical services include laboratory testing services for the
healthcare industry as an aid in the diagnosis and treatment of patients. We
operate a highly automated and centralized laboratory, which we believe has
significant economic advantages over other laboratory competitors. We market our
clinical testing services to managed care companies, insurance companies,
self-insured groups and physicians.

                                       2


      Our clinical services also include substance abuse testing services
provided to employers who adhere to drug screening guidelines. We are certified
by the Substance Abuse and Mental Health Services Administration to perform
substance abuse testing services for federally regulated employers and we
currently market these services throughout the country to both regulated and
nonregulated employers. Our rapid turnaround times and multiple testing options
help clients reduce downtime for affected employees and meet mandated drug
screening guidelines.



      On August 31, 2001, we purchased all of the outstanding capital stock of
Osborn Group, Inc., ("Osborn") a leading provider of laboratory testing and
other risk assessment services to the life insurance industry. Intellisys, Inc.,
Applied BioConcepts Inc. and Osborn Laboratories (Canada) Inc., wholly-owned
subsidiaries of Osborn, were included in the purchase. As a result of the
transaction, we were able to consolidate Osborn's testing and other operations
to our Lenexa, Kansas facility. To fund the acquisition and related expenses of
the transaction, Welsh, Carson, Anderson & Stowe, IX, L.P. and related
purchasers invested a total of $50 million, consisting of $35 million in
convertible preferred stock and $15 million in subordinated debt, in LabOne
pursuant to a Securities Purchase Agreement dated August 31, 2001. The
subordinated debt was prepaid on December 31, 2002. Funding for the prepayment
was obtained from our existing line of credit.

      Our principal executive offices are located at 10101 Renner Blvd., Lenexa,
Kansas 66219 and our telephone number is (913) 888-1770. Our corporate website
is www.labone.com. The information on our website does not constitute part of
this prospectus.

                                  RISK FACTORS


      Investing in shares of our common stock involves a risk of loss. You
should carefully consider the risk factors described below together with all of
the other information included in this prospectus and any prospectus supplement
and the other information that we have incorporated by reference before
investing in our common stock. If any of the matters included in the following
risk factors were to occur, our business, financial condition, results of
operations, cash flows or prospects could be materially adversely affected. In
such case, you could lose all or part of your investment.

If we cannot effectively implement our growth strategy, it would
materially affect our business and results of operations.

      Our growth strategy assumes we will acquire additional risk assessment,
laboratory testing or other related businesses and enter into new strategic
alliances. We cannot assure you that we will be able to continue to identify
risk assessment, laboratory testing or other related service companies to
acquire or enter into alliances with or otherwise negotiate acceptable terms
with respect to any transaction. Furthermore, we may have difficulty integrating
an acquired business with our existing operations, retaining key customers or
vendors, or retaining key personnel of the acquired business to work for us. The
acquisition and integration of an acquired business requires the dedication of
significant management resources that could adversely affect our business
activities or customer service. In addition, the issuance of equity securities
pursuant to these acquisitions or alliances could be dilutive to our existing
shareholders.

We derive a significant portion of our revenue from risk
assessment and laboratory testing services contracts, many of
which are terminable at will or on short notice by our customers.

      Our services are provided under arrangements that, in many instances, are
terminable at will or on short notice by our customers. Others are terminable or
subject to significant penalties if performance


                                       3


standards are not met. Competition, any interruption of, or deterioration in,
our services, or a change in management or ownership of a customer could result
in a customer's decision to stop using our services in whole or in part.

Lower prices offered by our competitors may undercut our
competitive advantage and reduce our profits.

      We have competed in the life insurance risk assessment business by
offering a more complete suite of higher quality services than our competitors
at competitive, but not low-end, prices. Some of our competitors are offering
our clients lower prices than we charge. If these competitors continue to reduce
prices and our customers refuse to pay higher prices for our services, our
profits may be reduced.

Competition from other providers of risk assessment, laboratory
testing or other related services may materially harm our
business.

      We have numerous competitors, including larger national laboratory
companies, that have significantly greater financial and technical resources
than that available to us. The strategies and other efforts of these competitors
may erode our customer base, reduce our sources of revenue and cause us to
reduce prices or increase our marketing and other costs of doing business, each
of which could have a material adverse affect on our results.

Any adverse change in the number and types of tests ordered by
life insurance companies could reduce our profits.

      Currently our largest and most profitable business segment is providing
risk assessment services to the life insurance industry. The level of demand for
such services is influenced by a number of factors, including:

     o    the number of life insurance applications written,

     o    the policy amount thresholds at which insurance companies order
          testing and other services that we provide,

     o    the type and costs of tests and other services requested, testing and
          specimen collection innovations approved by the Food and Drug
          Administration, and

     o    the extent to which insurance companies may create in-house testing
          facilities.

Many of these factors are beyond our control. Any adverse changes in life
insurance industry demand for testing and other services we provide could
significantly reduce our profits.

Cost-cutting in the heathcare industry could harm our business.

      Efforts by managed-care organizations, Medicare, Medicaid, insurance
companies and other payors to reduce the cost and utilization of healthcare
services, including laboratory testing services, could reduce the prices we may
be able to charge for our laboratory testing services and harm our business and
the results of our clinical laboratory operations.

                                      4


The low trading volume of our stock could limit your ability to
sell shares of our stock.

      The average daily trading volume of our common stock was approximately
35,500 shares during the first quarter of 2003, which is relatively low when
compared to other companies whose securities are listed for trading on a
national securities exchange or NASDAQ. This relatively low volume may make it
difficult for you to buy or sell shares of our common stock at desired prices
and may cause the price of our common stock to fluctuate significantly.

The large amount of goodwill on our books could depress our stock
price.

      As of December 31, 2002, we have $81.8 million of goodwill recorded on our
balance sheet. If this goodwill is impaired in the future, we will be required
to take a non-cash charge to earnings. This could depress the market price of
our stock if the stock price is influenced by investors that focus primarily on
net earnings rather than on earnings before interest, taxes, depreciation and
amortization.

The failure by us to provide accurate laboratory test results or
follow accepted procedures may result in claims that may not be
covered by our insurance.

      Our clients rely on the accuracy of our testing and other services to make
significant insurance, treatment and employment decisions. In addition, federal
and state laws regulate the disclosure of specimen testing results and other
nonpublic personal information. If we do not provide accurate test results using
accepted scientific methods or if we do not adequately protect the
confidentiality and security of this information, we could incur significant
liability. We have insurance to cover these types of claims, but we cannot
assure you either that this coverage is adequate or will continue to be
available at reasonable prices.

Our business could be harmed by disruption in express delivery
service.

      We generally rely on express couriers to transport specimens to our
laboratory quickly and safely. A disruption in these couriers' businesses
resulting from a labor dispute, natural disaster, malicious human acts or other
event could harm our business.

The development of more attractive on-site rapid assay tests may
reduce demand for our laboratory testing services.

      We serve customers through laboratory-based testing facilities. Although
there are some on-site rapid assay testing products available in the
marketplace, rapid assays have not achieved broad market acceptance due to the
high cost of such assays, difficulties in maintaining the confidentiality of
tests, liability concerns, regulatory limitations, less accurate testing
results and the absence of a broad testing menu. If more competitive assays
become available, such products could be substituted for laboratory based
testing and have an adverse impact on our business.

A natural disaster, telecommunications failure or similar event
affecting our only significant laboratory testing facility could
adversely affect our business.

      Our business could be adversely affected if our only significant testing
facility is temporarily shut down or severely damaged because of a natural
disaster, telecommunications failure or other serious event. We carry business
interruption insurance to compensate for losses which might occur, but we

                                       5



cannot provide assurance that this insurance coverage will be enough to
compensate for damages resulting from any such disruption to our business.

The interests of our principal stockholder may not be aligned
with your interests.

      Welsh, Carson, Anderson & Stowe IX, L.P. ("WCAS") and its related
investors beneficially own approximately 30% of our voting stock. WCAS also is
entitled to directly nominate or elect up to three members and jointly nominate
another member of our eight-member Board of Directors. In addition, WCAS and
certain members of the family of W. Thomas Grant, II, including certain related
trusts (the "Grant Family") have entered into a voting agreement pursuant to
which the Grant Family members have agreed to vote their shares of common stock
in the company in favor of director nominees of WCAS. As a result, WCAS will be
able to significantly influence matters affecting the company, including matters
submitted to a vote of our stockholders. Circumstances may occur in which the
interests of WCAS could be in conflict with your interests. Furthermore, it will
be difficult to successfuly conduct a proxy contest, or consummate a merger, a
tender offer, or similar transaction, without the support of WCAS.  In addition,
WCAS is a party to a standstill agreement with LabOne that prohibits WCAS from
taking certain actions that may result in a change of control of LabOne.

Our organizational documents and other agreements contain
restrictions which might prevent the takeover of our company or
change in our management.

      Provisions of our articles of incorporation and by-laws might have the
effect of discouraging a potential acquirer from attempting a takeover of us on
terms that some shareholders might favor, reducing the opportunity for our
shareholders to sell shares at a premium over then-prevailing market prices and
preventing or frustrating attempts to replace or remove current management.
These provisions include:

     o    a fair price provision,

     o    a requirement that our board of directors be classified,

     o    the authorization of a "blank check" preferred stock to be issued at
          the discretion of our board of directors, and

     o    a requirement that we receive advance notice of shareholder nominees
          for director and shareholder proposals.

     In addition, we have a shareholder rights plan, which grants shareholders
other than the acquiring person the right to purchase our common stock at
one-half of market price if any person becomes the beneficial owner of 15% or
more of the outstanding shares of common stock, subject to a number of
exceptions set forth in the plan.


                              SELLING STOCKHOLDERS


      On August 31, 2001, we purchased all of the outstanding capital stock of
Osborn. To fund the acquisition and related expenses of the transaction, WCAS
and related investors invested a total of $50 million in convertible preferred
stock and subordinated debt in LabOne pursuant to a Securities Purchase
Agreement dated August 31, 2001. In connection with this acquisition financing,
we issued warrants to WCAS and the related investors exercisable at $.01 per
share for 350,000 shares of our common stock.

                                      6




We are registering some of the shares of common stock underlying these warrants
pursuant to this registration statement.

      We are a party to several agreements with WCAS relating to its investment
in LabOne, including the Securities Purchase Agreement, a warrant agreement and
a registration rights agreement. WCAS and certain other stockholders of LabOne
are parties to a voting agreement relating to the stock of LabOne. The
agreements, and the terms of the Series B-1 Convertible Preferred Stock issued
to WCAS in the investment transaction, include provisions relating to the
composition of the Board of Directors of LabOne, rights of first refusal as to
certain future equity and debt offerings by LabOne and the right of WCAS to veto
certain actions or transactions by LabOne. The Series B-1 Convertible Preferred
Stock issued to WCAS provides for a cumulative dividend payable in kind, a
liquidation preference, conversion rights, anti-dilution provisions, redemption
rights, put/call rights, voting rights, rights in the election of directors and
certain veto rights.

     The following table sets forth:

     o    The names of the selling stockholders;

     o    The number and percent of our common stock that the selling
          stockholders owned prior to this offering (based on holdings that were
          convertible into or exercisable for common stock);

     o    The number of shares of our common stock that may be offered for the
          account of the selling stockholders pursuant to this prospectus; and

     o    The number and percent of our common stock to be held by the selling
          stockholders after the offering (based on holdings that were
          convertible into or exercisable for common stock and assuming all
          shares covered by this registration statement are sold by the selling
          stockholders).

      This information is based on information provided by the selling
stockholders and assumes the sale of all of the shares offered by the selling
stockholders. We are unable to determine the exact number of shares that will
actually be sold. The applicable percentages of ownership are based on an
aggregate of 11,328,219 shares of common stock issued and outstanding as of
April 30, 2003.

                                       9





                                             Shares Owned Prior To This  Shares Being   Shares Owned After This
                                                  Offering (1)(2)          Offered(3)       Offering (2)(4)
Selling Stockholder                            Number      Percent                         Number    Percent
                                                                                      

Welsh, Carson, Anderson & Stowe IX, L.P.       4,956,564    30.16%       273,799        4,682,765       28.99%
WCAS Management Corporation                        2,490      *              147            2,343         *
Patrick J. Welsh (6)                              19,079      *            1,302           17,777         *
Russell Carson (6)                                19,079      *            1,302           17,777         *
Bruce K. Anderson (6)                             18,943      *            1,303           17,640         *
Thomas E. McInerny (6)                            19,217      *            1,302           17,915         *
Robert A. Minicucci (6)                           19,217      *            1,302           17,915         *
Lawrence B. Sorrel                                19,217      *            1,302           17,915         *
Anthony J. De Nicola (7)                          13,892      *              938           12,954         *
Paul B. Queally (5)(7)                            10,350      *              703            9,647         *
IRA FBO Jonathan M. Rather (7)                     3,103      *              209            2,894         *
D. Scott Mackesy (5)(7)                            2,656      *              175            2,481         *
Sanjay Swani (7)                                     290      *               14              276         *
John D. Clark (7)                                    290      *               14              276         *


                                       7





                                             Shares Owned Prior To This  Shares Being   Shares Owned After This
                                                  Offering (1)(2)          Offered(3)       Offering (2)(4)
Selling Stockholder                            Number      Percent                         Number    Percent
                                                                                      

IRA FBO James R. Matthews (7)                        290      *               14              276         *
Sean Traynor (5)                                   2,069      *              140            1,929         *
John Almeida                                         294      *               18              276         *
Eric J. Lee                                          290      *               14              276         *



* Indicates less than 1%.

(1)   Based on holdings that were convertible into or exercisable for common
      stock as of May 19, 2003, including shares issuable as a result of the
      exercise of warrants and dividend accruals on convertible preferred stock
      through May 19, 2003.

(2)   Percentage ownership of the class assumes conversion of all convertible
      preferred stock and exercise of warrants held by the selling stockholders,
      but is otherwise presented on an undiluted basis assuming 11,328,219
      shares of common stock issued and outstanding.

(3)   Assumes exercise of the warrants by payment of the exercise price in cash.
      The number of shares offered would be slightly lower if the selling
      stockholders were to utilize the cashless exercise provision of the
      warrants.

(4)   Based on holdings that were convertible into or exercisable for common
      stock as of May 19, 2003, including shares issuable as a result of
      dividend accruals on convertible preferred stock through May 19, 2003.

(5)   Director of LabOne.

(6)   Managing member of the general partner of Welsh, Carson, Anderson & Stowe,
      IX, L.P. and stockholder of WCAS Management Corporation. Holder may be
      deemed to share power to vote or direct the voting of and to dispose or
      direct the disposition of the securities of LabOne owned by Welsh, Carson,
      Anderson & Stowe, IX, L.P. and WCAS Management Corporation. Holder
      disclaims beneficial ownership of all securities owned by such entities
      other than those he owns directly or by virtue of his indirect pro rata
      interest as managing member of the general partner of Welsh, Carson,
      Anderson & Stowe, IX, L.P. and as a stockholder in WCAS Management
      Corporation.

(7)   Managing member of the general partner of Welsh, Carson, Anderson & Stowe,
      IX, L.P. Holder may be deemed to share power to vote or direct the voting
      of and to dispose or direct the disposition of the securities of LabOne
      owned by Welsh, Carson, Anderson & Stowe, IX, L.P. Holder disclaims
      beneficial ownership of all securities owned by such entity other than
      those he owns directly or by virtue of his  indirect pro rata interest
      as managing member of the general partner of Welsh, Carson, Anderson
      & Stowe, IX, L.P.

                              PLAN OF DISTRIBUTION

      The shares of common stock offered by this prospectus are being registered
to allow public secondary trading by the holders of these shares from time to
time after the date of this prospectus. We will not receive any of the proceeds
from the offering of these shares by the selling stockholders. The timing,
manner and size of each sale will be determined by the selling stockholders, and
not by us.

      We have been advised by the selling stockholders that the shares offered
by this prospectus may be sold from time to time by or for the account of the
selling stockholders pursuant to this prospectus or, in some cases, pursuant to
Rule 144 under the Securities Act of 1933. Sales of shares pursuant to this
prospectus may be made in the over-the-counter market, on the Nasdaq National
Market or otherwise at prices and on terms then prevailing or at prices related
to the then current market price (in each case as

                                       8



determined by the selling stockholders). Sales may be made directly or through
agents designated from time to time, or through dealers or underwriters to be
designated or in negotiated transactions.

     The shares may be sold in one or more of the following ways:

     o    a block trade in which the seller's broker or dealer will attempt to
          sell the shares as agent but may position and resell a portion of the
          block as principal to facilitate the transaction;

     o    purchases by a broker or dealer as principal and resale by the broker
          or dealer for their account pursuant to this prospectus (as
          supplemented or amended to reflect such transaction to the extent
          required);

     o    an exchange distribution in accordance with the rules of the Nasdaq
          National Market;

     o    ordinary brokerage transactions and transactions in which the broker
          solicits purchasers;

     o    privately negotiated transactions;

     o    through put or call option transactions;

     o    through short sales; or

     o    an underwritten public offering.

     Some of the selling stockholders may distribute their shares, from time to
time, to their limited and/or general partners or members, who may sell their
shares pursuant to this prospectus (as supplemented or amended to reflect such
transaction to the extent required). Each selling stockholder may also transfer
shares owned by him by gift, and upon and such transfer, the donee may sell the
donee's shares pursuant to this prospectus (as supplemented or amended to
reflect such transaction to the extent required).

     A selling stockholder may enter into hedging transactions with
broker-dealers in connection with the distributions of the shares or otherwise.
In such transactions, broker-dealers may engage in short sales of the common
stock in the course of hedging the positions they assume with the selling
stockholder, including positions assumed in connection with distributions of the
shares by such broker-dealers. Some or all of the shares covered by this
registration statement may be sold to cover short positions in the open market.
A selling stockholder also may enter into option or other transactions with
broker-dealers that involve the delivery of the shares to the broker-dealers,
who may then resell or otherwise transfer such shares pursuant to this
prospectus (as supplemented or amended to reflect such transaction to the extent
required). In addition, a selling stockholder may loan or pledge shares to a
broker-dealer, which may sell the loaned shares or, upon a default by the
selling stockholder of the secured obligation, may sell or otherwise transfer
the pledged shares pursuant to this prospectus (as supplemented or amended to
reflect such transaction to the extent required).

      The selling stockholders may sell shares directly to other purchasers,
through agents or through broker-dealers. Any selling agents or broker-dealers
may receive compensation in the form of underwriting discounts, concessions or
commissions from the selling stockholders, from purchasers of shares for whom
they act as agents, or from both sources. That compensation may be in excess of
customary commissions.

                                       9


      The selling stockholders and any broker-dealers that participate in the
distribution of the shares may be deemed to be "underwriters" within the meaning
of the Securities Act of 1933, as amended, in connection with the sales. Any
commissions, and any profit on the resale of shares, received by the selling
stockholders and any such broker-dealers may be deemed to be underwriting
discounts and commissions. We have been advised by each of the selling
stockholders that they have not, as of the date of this prospectus, entered into
any arrangement with any agent, broker or dealer for the sale of the shares.

      We have advised the selling stockholders that the anti-manipulation rules
of Regulation M under the Securities Exchange Act of 1934, as amended, may apply
to sales of common stock in the market and to the activities of the selling
stockholders and their affiliates. In addition, we will make copies of this
prospectus available to the selling stockholders and have informed each of them
of the need for delivery of copies of this prospectus to purchasers at or prior
to the time of any sale of the shares offered hereby.

      We may suspend the use of this prospectus and any supplements hereto in
certain circumstances due to pending corporate developments, public filings with
the SEC or similar events.

      We will pay all costs and expenses incurred by us in connection with the
registration of the sale of shares pursuant to this prospectus. We will not be
responsible for any commissions, underwriting discounts or similar charges on
sales of the shares.

                                 USE OF PROCEEDS

      We will not receive any of the proceeds from the sale of common stock by
the selling stockholders.

                                  LEGAL MATTERS

      The validity of the common stock offered hereby will be
passed upon for us by Joseph C. Benage, Executive Vice President,
General Counsel and Secretary of the company.  Mr. Benage is a
full-time employee and officer and beneficially owns 81,768
shares of our common stock.

                                     EXPERTS

      The consolidated financial statements of LabOne, Inc. as of December 31,
2002 and 2001, and for each of the years in the three-year period ended December
31, 2002, have been incorporated by reference herein in reliance upon the report
of KPMG LLP, independent accountants, incorporated by reference herein, and upon
the authority of said firm as experts in accounting and auditing. The audit
report covering the December 31, 2002 and 2001 consolidated financial statements
refers to the adoption of Statement of Financial Accounting Standards No. 141,
"Business Combinations" and No. 142, "Goodwill and Other Intangible Assets."

                                       10


                                     PART II

                     INFORMATION NOT REQUIRED IN PROSPECTUS

ITEM 14.  OTHER EXPENSES OF ISSUANCE AND DISTRIBUTION

      The following table sets forth the costs and expenses payable by LabOne in
connection with the issuance and distribution of the common stock being
registered. All amounts are estimates except the SEC registration fee.




SEC registration fee                                     $ 469
Legal fees and expenses                                 16,000
Accounting fees and expenses                            10,000
Miscellaneous fees and expenses                          1,000
                                                      --------
Total                                                 $ 27,469
                                                      ========



ITEM 15.  INDEMNIFICATION OF DIRECTORS AND OFFICERS

      We are incorporated under the laws of the state of Missouri. Under Section
351.355 of the General and Business Corporation Law of Missouri, we may, under
specified circumstances, indemnify any of our directors, officers, employees or
agents who is or was a party or is threatened to be made a party to any
threatened, pending or completed action, suit or proceeding by reason of the
fact that such person is or was a director, officer, employee or agent of the
company, against expenses, including attorneys' fees, judgments, fines and
amounts paid in settlement, actually and reasonably incurred by such person in
connection with such action, suit or proceeding. Section 351.355 provides that
the indemnification provided by the section shall not be deemed exclusive of any
other rights to which those seeking indemnification may be entitled under the
articles of incorporation or by-laws of LabOne or any agreement, vote of
shareholders, disinterested directors or otherwise. Under Section 351.355, we
may purchase and maintain insurance on behalf of any person who is or was a
director, officer, employee or agent of the company against any liability
asserted against such person and incurred by such person in any such capacity,
or arising out of such person's status as such, whether or not we would have the
power to indemnify such person against such liability under the provisions of
Section 351.355.

      Article IV of our bylaws provides that each person who is or was a
director, officer or employee of the company shall be indemnified by us as of
right to the full extent permitted or authorized by the laws of the state of
Missouri, as now in effect and as hereafter amended, against any liability,
judgment, fine, amount paid in settlement, cost and expense (including
attorneys' fees) asserted or threatened against and incurred by such person in
his or her capacity as or arising out of his or her status as a director,
officer or employee of the company. Article IV of our bylaws also provides that
no person shall be liable to the company for any loss, damage, liability or
expense suffered by the company on account of any action taken or omitted to be
taken by him or her as a director, officer or employee of the company if such
person (i) exercised the same degree of care and skill as a prudent man would
have exercised under the circumstances in the conduct of his own affairs or (ii)
took or omitted to take such action in reliance upon the advice of counsel or
upon statements made or information furnished by directors, officers, employees
or agents of the company which such person had no reasonable grounds to
disbelieve.


                                  II-1



      We have entered into indemnification agreements with our directors and
officers under which we have agreed to indemnify such persons against expenses,
judgments and fines incurred in connection with the defense or settlement of
actions, suits or proceedings, provided such persons' conduct is not finally
adjudged to have been knowingly fraudulent, deliberately dishonest or willful
misconduct.

      An Agreement and Plan of Merger between the former LabOne, Inc. and us
provides for certain indemnification of officers and directors as well as former
officers and directors of the company, as described under "The Merger Agreement-
Indemnification" in the Joint Proxy Statement/Prospectus contained in Amendment
No. 4 to the registrant's Registration Statement on Form S-4, registration no.
333-76131, filed with the Commission on July 2, 1999.

      Article IV of our bylaws authorizes us to purchase and maintain insurance
on behalf of any director, officer or employee, trustee or agent of the company
against any liability asserted against such person or incurred by such person
in any such capacity or status, whether or not we would have power to indemnify
such person against such liability. We currently maintain directors' and
officers' liability insurance to insure our directors and officers against
certain liabilities incurred in their capacities as such.

ITEM 16.  EXHIBITS

      The index to exhibits appears immediately following the signature pages
to this Registration Statement.


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:

      (i) 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 20 percent change in the maximum
      aggregate offering price set forth in the "Calculation of Registration
      Fee" table in the effective registration statement.

      (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 paragraphs (i) and (ii) above do not apply if the
      information required to be included in a post-effective amendment by
      those paragraphs is contained in periodic reports

                                      II-2


      filed with or furnished to the Commission by the registrant pursuant to
      Section 13 or Section 15 of the Securities Exchange Act of 1934 that are
      incorporated by reference in the registration statement.

      (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.

      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.

      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 provisions referred to in Item 15 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 Securities Act, and is, therefore, unenforceable. In the event that a
claim for indemnification against such liabilities (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 hereunder, 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 of whether such indemnification by it is against public policy as
expressed in the Securities Act and will be governed by the final adjudication
of such issue.


                                      II-3



                                   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
Pre-Effective Amendment No. 1 to the Registration Statement to be signed on
its behalf by the undersigned, thereunto duly authorized, in the City of
Lenexa, State of Kansas, on this 23rd day of May, 2003.


                                LABONE, INC.



                                By: */s/ W. Thomas Grant II
                                    -------------------------------------
                                    W. Thomas Grant II
                                    Chairman of the Board, President and
                                    Chief Executive Officer



      PURSUANT TO THE REQUIREMENTS OF THE SECURITIES ACT OF 1933, AS AMENDED,
THIS PRE-EFFECTIVE AMENDMENT NO. 1 TO THE REGISTRATION STATEMENT HAS BEEN
SIGNED BY THE FOLLOWING PERSONS IN THE CAPACITIES AND ON THE DATES INDICATED:


       SIGNATURE                   TITLE                             DATE

* /s/ W. Thomas Grant II    Chairman of the Board,              May  23, 2003
------------------------    President and Chief
W.Thomas Grant II           Executive Officer
                            (Principal Executive Officer)

* /s/ John W. McCarty       Executive Vice President            May  23, 2003
---------------------       and Chief Financial Officer
John W. McCarty             (Principal Financial and
                            Accounting Officer)

*  /s/ W/ Roger Drury       Director                            May  23, 2003
---------------------
W. Roger Drury

* /s/ D. Scott Mackesy      Director                            May  23, 2003
----------------------
D. Scott Mackesy


* /s/ Paul B. Queally       Director                            May  23, 2003
---------------------
Paul B. Queally


                                      II-4


* /s/ James R. Seward       Director                            May  23, 2003
---------------------
James R. Seward


* /s/ Sean M. Traynor       Director                            May  23, 2003
---------------------
Sean M. Traynor

* /s/ John E. Walker        Director                            May  23, 2003
--------------------
John E. Walker


*By: /s/ Joseph C. Benage
-------------------------
Joseph C. Benage
Attorney-in-Fact




                                      II-5



                                  EXHIBIT INDEX

EXHIBIT
NO.                             DESCRIPTION

4.1        Amended Articles of Incorporation - attached as Exhibit B to
           Appendix A to the Joint Proxy Statement/Prospectus filed as a part
           of the Registrant's Registration Statement on Form S-4, filed
           July 2, 1999 (File No. 333-76131) and incorporated herein by
           reference.

4.2        Amended and Restated Bylaws - attached as Exhibit C to Appendix A to
           the Joint Proxy Statement/Prospectus filed as a part of the
           Registrant's Registration Statement on Form S-4, filed July 2, 1999
           (File No. 333-76131) and incorporated herein by reference.

4.3        Specimen certificate for shares of the registrant's common stock
           (incorporated by reference from Exhibit (4) of the Form 8-A/A
           amendment filed September 7, 1999 to registrant's registration
           statement on Form 8-A under the Securities Exchange Act of 1934).

4.4        Rights Agreement and attached exhibits A, B and C, dated as of
           February 11, 2000, between the Registrant and American Stock
           Transfer & Trust Company-- attached as Exhibit 4.1 to the
           Registrant's Form 8-K Current Report, filed February 14, 2000 and
           incorporated herein by reference.

4.5        Amendment No. 1 to Rights Agreement dated August 31, 2001 between
           LabOne, Inc. and American Stock Transfer & Trust Company-- attached
           as exhibit 4.6 to the Current Report on Form 8-K filed October 5,
           2001 and incorporated herein by reference.

5.1*       Opinion of Joseph C. Benage, Executive Vice President,
           General Counsel and Secretary of the Registrant.

23.1       Consent of KPMG LLP.

23.2*      Consent of Joseph C. Benage, Executive Vice President,
           General Counsel and Secretary of the Registrant
           (included in Exhibit 5.1).

24.1*      Power of Attorney.

--------------------------
* Previously filed.