As filed with the Securities and Exchange Commission on July 21, 2006

                                                     Registration No. 333-135158

================================================================================

                                  UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION
                              WASHINGTON, DC 20549

                            -------------------------

                                 AMENDMENT NO. 1

                                       TO

                                    FORM S-3

                          REGISTRATION STATEMENT UNDER
                           THE SECURITIES ACT OF 1933

                             ----------------------

                            CAS MEDICAL SYSTEMS, INC.
             (Exact Name of Registrant as Specified in Its Charter)

            Delaware                                    06-1123096
(State or Other Jurisdiction of          (I.R.S. Employer Identification Number)
 Incorporation or Organization)

              44 EAST INDUSTRIAL ROAD, BRANFORD, CONNECTICUT 06405
                                 (203) 488-6056
               (Address, Including Zip Code, and Telephone Number,
        Including Area Code, of Registrant's Principal Executive Offices)

                                 LOUIS P. SCHEPS
                      PRESIDENT AND CHIEF EXECUTIVE OFFICER
                            CAS MEDICAL SYSTEMS, INC.
                             44 EAST INDUSTRIAL ROAD
                           BRANFORD, CONNECTICUT 06405
                                 (203) 488-6056
            (Name, Address, Including Zip Code, and Telephone Number,
                   Including Area Code, of Agent for Service)

                                    COPY TO:
                              Michael Grundei, Esq.
                               Wiggin and Dana LLP
                               400 Atlantic Street
                           Stamford, Connecticut 06901
                                 (203) 363-7600

     Approximate date of commencement of proposed sale to public: From time to
time after this registration statement has been declared effective.

     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, 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. [ ]

     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.




PROSPECTUS



                                1,486,500 Shares

                            CAS MEDICAL SYSTEMS, INC.

                                  Common Stock

                              --------------------

     This prospectus relates to the offer and sale of up to 1,486,500 shares of
our common stock, including up to 1,279,000 shares issuable upon the exercise of
presently exercisable warrants by the selling stockholders listed on page 13,
including their transferees, pledgees or donees or their respective successors.

     The prices at which these shares may be sold will be determined by the
prevailing market price for shares of our common stock, in negotiated
transactions or otherwise. We will not receive any of the proceeds from the sale
of these shares. We could receive up to approximately $0.6 million upon payment
of the exercise price of the warrants. We intend to use any such proceeds for
general working capital.

     Our common stock is listed on the Nasdaq Capital Market under the symbol
"CASM". On July 20, 2006, the last reported sale price for our common stock was
$6.15 per share.


                             ----------------------

     INVESTING IN OUR COMMON STOCK INVOLVES RISKS. SEE "RISK FACTORS," BEGINNING
ON PAGE 3 OF THIS PROSPECTUS.

                             -----------------------

     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.




                     This prospectus is dated July 21, 2006.










                                TABLE OF CONTENTS

                                                                          PAGE

Summary.....................................................................1

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

Special Note on forward-Looking Statements..................................6

Use of Proceeds.............................................................6

Selling Stockholders........................................................7

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

Legal Matters...............................................................9

Experts.....................................................................9

Where You Can Find More Information........................................10

Indemnification for Securities Act Violations..............................10

Part II  Information Not Required in Prospectus..........................II-1


     This prospectus is part of a registration statement that we filed with the
Securities and Exchange Commission using a "shelf" registration or continuous
offering process. Under this shelf process, selling stockholders may from time
to time sell the securities described in this prospectus in one or more
offerings.

     This prospectus provides you with a general description of the securities
that the selling stockholders may offer. Each time a selling stockholder sells
securities, that selling stockholder is required to provide you with a
prospectus and/or a prospectus supplement containing specific information about
the selling stockholder and the terms of the securities being offered. A
prospectus supplement may include other special considerations applicable to
those securities. The prospectus supplement may also add, update or change
information in this prospectus. If there is any inconsistency between the
information in this prospectus and any prospectus supplement, you should rely on
the information in the prospectus supplement. You should read both this
prospectus and any prospectus supplement together with the additional
information described under the heading "Where You Can Find More Information."

     The registration statement, of which this prospectus is a part, including
the exhibits to the registration statement, provides additional information
about us and the securities offered by the selling stockholders under this
prospectus. The registration statement, including the exhibits, can be read on
the website maintained by the Securities and Exchange Commission or at the
offices of the Securities and Exchange Commission as set forth under the heading
"Where You Can Find More Information."

     YOU SHOULD RELY ONLY ON THE INFORMATION CONTAINED OR INCORPORATED BY
REFERENCE IN THIS PROSPECTUS. WE HAVE NOT, AND THE SELLING STOCKHOLDERS HAVE
NOT, AUTHORIZED ANYONE TO PROVIDE YOU WITH INFORMATION DIFFERENT FROM THAT
CONTAINED OR INCORPORATED BY REFERENCE IN THIS PROSPECTUS. THIS PROSPECTUS IS
NOT AN OFFER TO SELL, NOR IS IT SEEKING AN OFFER TO BUY, SHARES OF OUR COMMON
STOCK IN ANY JURISDICTION IN WHICH THE OFFER OR SALE IS NOT 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 COMMON STOCK.



                                     SUMMARY

     THIS SUMMARY MAY NOT CONTAIN ALL THE INFORMATION THAT MAY BE IMPORTANT TO
YOU. YOU SHOULD READ THE ENTIRE PROSPECTUS, INCLUDING THE FINANCIAL DATA AND
RELATED NOTES AND OTHER INFORMATION INCORPORATED BY REFERENCE, BEFORE MAKING AN
INVESTMENT DECISION. THE TERMS "CAS," "WE," "US," AND "OUR" REFER TO CAS MEDICAL
SYSTEMS, INC.

THE COMPANY

We are a Delaware corporation organized in 1984. We design, manufacture and
market medical products, specifically blood pressure measurement technology,
blood pressure cuffs, vital signs measurement equipment, cardio-respiratory
monitoring equipment and supplies for neonatal intensive care. Our products are
designed to improve the quality of patient care and provide exceptional value
and performance. We have several products in various stages of development that
we believe will add to and complement our current product lines.

On May 15, 2005, we completed the purchase of all of the outstanding capital
stock of Statcorp, Inc. from its stockholders for cash. The cost of the
acquisition was $4.8 million including a post-closing working capital adjustment
and direct acquisition costs. An additional purchase adjustment will be required
based upon post-closing revenues of Statcorp for the twelve month period
following the closing date. Statcorp, a privately-owned company based in
Jacksonville, Florida, develops, assembles and sells liquid infusion devices,
blood pressure cuffs, and blood transfusion filters for worldwide use in the
medical industry.

PRINCIPAL PRODUCTS AND SERVICES

BLOOD PRESSURE MEASUREMENT TECHNOLOGY

We have developed a proprietary non-invasive blood pressure technology,
MAXNIBP(R). We believe this technology is more accurate, reliable, and able to
produce a measurement result faster than our competitors' technology. These
advantages strengthen our competitive position, especially in clinical
situations where measurements can be difficult. We have entered into original
equipment manufacturer ("OEM") agreements to supply our MAXNIBP technology in
the form of modules to various companies throughout the world. These modules are
used in larger monitoring systems where non-invasive blood pressure is but one
measurement parameter. Our OEM agreements are typically multi-year arrangements.

BLOOD PRESSURE CUFFS

We offer a full line of disposable and reusable blood pressure cuffs. The
product line includes cuffs and pressure infusers manufactured by Statcorp, Inc.
which we purchased in 2005. The blood pressure cuffs can be used on patients
from neonate through adult, as well as veterinary patients, and complement our
MAXNIBP blood pressure measurement technology.

VITAL SIGNS MONITORING EQUIPMENT

We offer two platforms of vital signs monitors incorporating various
combinations of measurement parameters. The product lines include options for
measurement of non-invasive blood pressure using the our proprietary MAXNIBP
technology, pulse oximetry, electro-cardiography, temperature, and capnography.
CAS monitors are ideal for a range of clinical settings (both human and
veterinary) including emergency medical service, medical/surgical units,
out-patient care, and procedural sedation. We also offer a full line of
disposable and reusable blood pressure cuffs to complement our monitors.

                                        1


CARDIO-RESPIRATORY MONITORING EQUIPMENT

The CAS line of cardio-respiratory monitors is used to monitor apnea in
home-based and hospital settings. Our product line includes two of the
industry's best selling infant apnea monitoring products and has the broadest
range of capabilities available. The AMI(R) and 511 monitors allow
cardio-respiratory and pulse oximetry monitoring and recording for a range of
patients. Proprietary CAS EXPRESS(R) software saves patient data from the
monitors and generates reports for review by the clinician.

SUPPLIES FOR NEONATAL INTENSIVE CARE

Our specialty neonatal supplies are a foundation of our business. We have a long
record of producing high quality products designed specifically to meet the
unique needs of neonatal intensive care. The varied product line includes
Klear-Trace(R) ECG Electrodes, NeoGuard(R) skin temperature probes and adhesive
reflectors, SoftCheck(R) neonatal blood pressure cuffs, BiliBottoms(TM) light
permeable diapers for use during phototherapy, and the Premie Nestie(R) neonatal
positioning device.

THE OFFERING

Common Stock offered by           1,486,500 (includes 1,279,000 shares issuable
Selling Stockholders              upon exercise of warrants held by Selling
                                  Stockholders.)

Use of Proceeds                   We will not receive any proceeds from the sale
                                  of shares in this offering.

Nasdaq Capital Market Symbol      CASM


                                ----------------

     Our principal executive offices are located at 44 East Industrial Road,
Branford, Connecticut 06405, and our telephone number is (203) 488-6056. We
maintain a website at WWW.CASMED.COM where general information about us is
available. We are not incorporating the contents of the website into this
prospectus.

                                        2


                                  RISK FACTORS

     OUR BUSINESS FACES MANY RISKS. IF ANY OF THE EVENTS OR CIRCUMSTANCES
DESCRIBED IN THE FOLLOWING RISK FACTORS ACTUALLY OCCUR, OUR BUSINESS, FINANCIAL
CONDITION OR RESULTS OF OPERATIONS COULD SUFFER, AND THE TRADING PRICE OF OUR
COMMON STOCK COULD DECLINE. THE RISKS DESCRIBED BELOW MAY NOT BE THE ONLY RISKS
WE FACE. ADDITIONAL RISKS THAT WE DO NOT YET KNOW OF OR THAT WE CURRENTLY
BELIEVE ARE IMMATERIAL MAY ALSO IMPAIR OUR BUSINESS OPERATIONS. YOU SHOULD
CONSIDER THE FOLLOWING RISKS, AS WELL AS THE OTHER INFORMATION INCLUDED OR
INCORPORATED BY REFERENCE IN THIS PROSPECTUS BEFORE DECIDING TO INVEST IN OUR
COMMON STOCK.


     WE ARE A SMALL COMPANY IN A HIGHLY COMPETITIVE INDUSTRY.

     We are engaged in a rapidly evolving field. Competition from other medical
device companies, diversified healthcare companies and research and academic
institutions is intense and expected to increase. Many companies engaged in the
medical device sector have substantially greater financial and other resources
and development capabilities than we do, and have substantially greater
experience in testing of products, obtaining regulatory approvals and
manufacturing and marketing medical devices. Therefore, our competitors may
succeed in obtaining approval for products more rapidly than we can. Other
companies may succeed in developing and commercializing products earlier than we
do. In addition to competing with universities and other research institutions
in the development of products, technologies and processes, CAS Medical Systems
may compete with other companies in acquiring rights to products or technologies
from universities. Also, the medical device market is experiencing increasing
customer concentration, due to the emergence of large purchasing groups. We
cannot assure you that we will develop products that are more effective or
achieve greater market acceptance than competitive products, or that our
competitors will not succeed in developing products and technologies that are
more effective than those being developed by us or that would render our
products and technologies less competitive or obsolete. Moreover, there can be
no assurance that we will be able to successfully sell to large purchasing
groups, which are increasingly looking to suppliers that can provide a broader
range of products than we currently offer.

     THE SALE OF OUR PRODUCTS MAY RESULT IN SIGNIFICANT PRODUCT LIABILITY
EXPOSURE.

     As a manufacturer of medical diagnostic equipment, we could face product
liability claims. We maintain product liability insurance in an aggregate amount
of $5 million. We cannot assure you that this insurance coverage will be
adequate to cover any product liability claims that occur in the future or that
product liability insurance will continue to be available at reasonable prices.
Any product liability judgments or settlements in excess of insurance coverage
could have a material adverse effect on our business and results of operations.

     WE ARE SUBJECT TO SIGNIFICANT GOVERNMENT REGULATION.

     Our business is subject to varying degrees of governmental regulation in
the countries in which we operate. In the United States, our products are
subject to regulation as medical devices by the United States Food and Drug
Administration (the "FDA"), and by other federal and state agencies. These
regulations pertain to the manufacturing, labeling, development and testing of
our devices as well as to the maintenance of required records. An FDA regulation
also requires prompt reporting by all medical device manufacturers of an event
or malfunction involving a medical device where the device caused or contributed
to death or serious injury or is likely to do so.

     Federal law provides for several routes by which the FDA reviews medical
devices before their entry into the marketplace. Medical products of the type
currently being marketed and under

                                        3


development by us are subject to regulation under the Food, Drug and Cosmetic
Act (the "FDC Act") and numerous acts and amendments such as the Quality System
Regulations which replaced the regulations formerly called Good Manufacturing
Practices. In addition, depending upon product type, we must also comply with
those regulations governing the Conduct of Human Investigations, Pre-Market
Approval Regulations and other requirements, as promulgated by the FDA. The FDA
is authorized to inspect a device, its labeling and advertising, and the
facilities in which it is manufactured in order to ensure that the device is not
manufactured or labeled in a manner which could cause it to be injurious to
health.

     The FDA has adopted regulations which classify medical devices based upon
the degree of regulation believed necessary to assure safety and efficacy. A
device is classified as a Class I, II, or III device. Class I devices are
subject only to general controls. Class II devices, in addition to general
controls, are or will be subject to "performance standards." Most devices are
also subject to the 510(k) pre-market notification provision. In addition, some
Class III devices require FDA pre-market approval before they may be marketed
commercially because their safety and effectiveness cannot be assured by the
general controls and performance standards of Class I or II devices. Our
products are primarily Class I and II devices and several of them have required
FDA notification under Section 510(k) of the FDC Act.

     Satisfaction of clearance or approval requirements may take up to several
years or more and may vary substantially based upon the type, complexity and
novelty of the product. The effect of government regulation may be to delay
marketing of new products for a considerable or indefinite period of time, to
impose costly procedures upon our activities and to furnish a competitive
advantage to larger companies that compete with us. We cannot assure you that
FDA or other regulatory clearance or approval for any products we develop will
be granted on a timely basis, if at all, or, once granted, that clearances or
approvals will not be withdrawn or other regulatory action taken which might
limit our ability to market our proposed products. Any delay in obtaining or
failure to obtain these clearances or approvals would adversely affect the
manufacturing and marketing of our products and the ability to generate
additional product revenue.

     WE RELY TO A SIGNIFICANT DEGREE ON OUR PROPRIETARY RIGHTS.

     We rely on a combination of patents, trade secrets, trademarks and
non-disclosure agreements to protect our proprietary rights. We cannot assure
you that our patent applications will result in the issuance of patents or that
any patents owned by us now or in the future will afford protection against
competitors that develop similar technology. We also cannot assure you that our
non-disclosure agreements will provide meaningful protection for our trade
secrets or other proprietary information. Moreover, in the absence of patent
protection, our business may be adversely affected by competitors who
independently develop substantially equivalent or superior technology.

     It is possible that we may need to acquire licenses to, or to contest the
validity of, issued or pending patents of third parties relating to our
technology or to products presently marketed or under development by us. In
addition, we cannot assure that any license required under any patent would be
made available to us on acceptable terms, if at all, or that we would prevail in
any patent litigation.

     OUR PRODUCTS MAY BECOME RAPIDLY OBSOLETE.

     The areas in which we are developing, distributing, and/or licensing
products involve rapidly developing technology. Others may develop products that
might cause products being developed, distributed or licensed by us to become
obsolete or uneconomical or result in products superior to our products.

                                        4


     OUR INTERNATIONAL SALES SUBJECT US TO CURRENCY AND RELATED RISKS.

     Our international sales accounted for 18.6% of our total net sales for the
2005 fiscal year. We expect that international sales will continue to constitute
a significant portion of our business. Although we sell our products in United
States dollars and are not subject to significant currency risks, an increase in
the value of the United States dollar relative to foreign currencies in our
international markets could make our products less price competitive in these
markets.

     AN ACQUISITION OF CAS MEDICAL SYSTEMS MAY BE HINDERED.

     Our Board of Directors is also authorized to issue from time to time,
without stockholder authorization, shares of preferred stock, in one or more
designated series or classes. We are also subject to a Delaware statute
regulating business combinations. These provisions could discourage, hinder or
preclude an unsolicited acquisition of CAS Medical Systems, Inc. and could make
it less likely that stockholders receive a premium for their shares as a result
of any takeover attempt.

     THIS OFFERING MAY NEGATIVELY IMPACT THE TRADING PRICE OF OUR COMMON STOCK.

     Sales of a substantial number of shares of our common stock in the public
market originally issued through the exercise of options or warrants could
adversely affect the market price of our common stock and may also adversely
affect our ability to raise additional capital. 1,486,500 shares of our common
stock are being registered in connection with this prospectus for resale to the
public. The common stock registered in connection with this prospectus would,
upon exercise of the relevant warrants, constitute approximately 12.69% of our
common stock based on 10,430,586 shares outstanding as of March 31, 2006 plus
the 1,279,000 shares of warrant stock registered pursuant to the registration
statement of which this prospectus is a part. Historically, our common stock has
been thinly traded. This low trading volume may have had a significant effect on
the market price of our common stock, which may not be indicative of the market
price in a more liquid market.

     WE DEPEND HIGHLY ON CERTAIN KEY MANAGEMENT PERSONNEL.

     We believe that our future success will depend to a significant extent on
the efforts and abilities of our senior management, in particular Louis P.
Scheps, our Chairman of the Board, President and Chief Executive Officer and
Andrew Kersey, our Chief Operating Officer. The loss of the services of Mr.
Scheps or Mr. Kersey could have a material adverse effect on our business and
results of operations.

     WE DO NOT EXPECT TO PAY CASH DIVIDENDS.

     We have not paid cash dividends on our common stock since inception, and at
this time we do not anticipate that we will pay cash dividends in the
foreseeable future.

                                        5


                   SPECIAL NOTE ON FORWARD-LOOKING STATEMENTS

     This prospectus and the documents incorporated by reference herein, contain
"forward-looking statements." These statements may be made directly in this
prospectus or in documents incorporated by reference herein. Words such as
"anticipate," "estimate," "expect," "project," "intend," "plan," "believe" and
words and terms of similar substance used in connection with any discussion of
future operating or financial performance, identify forward-looking statements.
All forward-looking statements constitute our present estimates of future events
and are subject to a number of factors and uncertainties, including, without
limitation, the risks discussed in "Risk Factors", that could cause actual
results to differ materially from those described in the forward-looking
statements. In addition, the risks related to our business, among others, could
cause actual results to differ materially from those described in the
forward-looking statements. You are cautioned not to place undue reliance on the
forward-looking statements, which speak only as of the date of this prospectus
or as of the date of any document incorporated by reference in this prospectus,
as applicable. We are not under any obligation, and expressly disclaim any
obligation, to update or alter any forward-looking statements, whether as a
result of new information, future events or otherwise.

                                 USE OF PROCEEDS

     We will not receive any of the proceeds from the sale of the common stock
by the selling stockholders. All proceeds will be for the account of the selling
stockholders, as described below. See "Selling Stockholders" and "Plan of
Distribution." We would receive up to approximately $0.6 million upon payment of
the exercise price of the warrants. We intend to use any such proceeds for
general working capital.











                                        6


                              SELLING STOCKHOLDERS

     This prospectus relates to the offer and sale from time to time by the
selling stockholders, including their transferees, pledgees or donees or their
respective successors of up to 1,486,500 shares of common stock, including up to
1,279,000 shares of common stock issuable upon the exercise of presently
exercisable warrants.

     The selling stockholders listed in the table below may have sold or
transferred, in transactions exempt from the registration requirements of the
Securities Act of 1933, as amended, some or all of their common stock since the
date as of which the information in the table is presented. Information about
the selling stockholders may change over time. Any changed information will be
set forth in an amendment to the registration statement or supplement to this
prospectus, as required by law.

     None of the selling stockholders nor any of their affiliates, officers,
directors or principal equity holders has held any position or office or has had
any material relationship with us within the past three years, except as set
forth in the footnotes to the table below. None of the selling stockholders are
broker-dealers or affiliated with a broker-dealer, except as set forth in the
footnotes to the table below.

     The shares of common stock offered herein were issued or are issuable
pursuant to warrants that the company granted to the selling stockholders at
various times as compensation for their services as directors of the company.

     The following table contains information furnished to us by the selling
stockholders, with respect to the selling stockholders and the common stock
beneficially owned by each selling stockholder that may be offered under this
prospectus. We prepared this table based on information supplied to us by the
selling stockholders named in the table and have not sought to verify such
information.


                                                                                                                PERCENTAGE OF
                                   SHARES OF COMMON STOCK        SHARES OF        SHARES OF COMMON STOCK         COMMON STOCK
                                  BENEFICIALLY OWNED PRIOR     COMMON STOCK      BENEFICIALLY OWNED AFTER     BENEFICIALLY OWNED
NAME OF SELLING STOCKHOLDER           TO OFFERING (1)           BEING SOLD               OFFERING            AFTER THE OFFERING (2)
                                                                                                        
  Louis P. Scheps(3)                   1,094,925 (4)            919,000 (5)              275,925                    2.58%
  Myra Josephson(6)                       75,000 (7)             75,000 (7)                    0                        *
  Lawrence S. Burstein(8)                245,625 (9)           157,500 (10)               88,125                        *
  Jerome Baron(11)                       235,450(12)                207,500               27,950                        *
  Jay M. Haft(13)                         60,000(14)            60,000 (14)                    0                        *
  Saul S. Milles, M.D.(15)               71,250 (16)             67,500(17)                3,750                        *

--------------

                                        7


*    Less than 1%

(1)  Includes shares of common stock held on May 24, 2006 in the case of Mr.
     Scheps, May 25, 2006 in the case of Mr. Haft, Mr. Milles and Mr. Baron, May
     30, 2006 in the case of Mrs. Josephson and May 31, 2006 in the case of Mr.
     Burstein and shares of common stock issuable upon the exercise of warrants
     or options held by the applicable selling stockholder which are exercisable
     within 60 days of such applicable date.

(2)  This percentage is calculated using as the numerator, the number of shares
     of common stock included in the prior column and as the denominator,
     10,430,586 shares of common stock outstanding as of March 31, 2006 plus the
     number of shares of common stock, if any, issuable upon the exercise of
     warrants or options held by the selling shareholder, assuming the sale by
     the selling shareholder of all of his or her shares covered by this
     prospectus.

(3)  Mr. Scheps is Chairman of the Board, President and Chief Executive Officer
     and a director of the Company.

(4)  Includes warrants to purchase 819,000 shares and options to purchase 50,000
     shares, each exercisable within 60 days.

(5)  Consists of common stock underlying warrants to purchase 819,000 shares
     exercisable within 60 days and warrants to purchase 100,000 shares
     exercisable only upon a change in control.

(6)  Myra Josephson's husband was a director of the company prior to his death
     in July 1996.

(7)  Consists of common stock underling warrants to purchase 75,000 shares.

(8)  Mr. Burstein is a director of the company.

(9)  Includes warrants to purchase 157,500 shares and options to purchase 3,750
     shares exercisable within 60 days. Also includes 9,375 shares owned
     directly and indirectly by a family member and 75,000 shares held in Mr.
     Burstein's IRA rollover account.

(10) Consists of common stock underlying warrants to purchase 157,500 shares.

(11) Mr. Baron is a director of the company. Mr. Baron is also Vice-Chairman of
     Brean Murray, Carret and Co., LLC (formerly Brean Murray Securities Inc), a
     registered broker-dealer.

(12) Includes options to purchase 3,750 shares exercisable within 60 days.

(13) Mr. Haft was a director of the company until October 1996.

(14) Consists of common stock underlying warrants to purchase 60,000 shares.

(15) Dr. Milles is a director of the company.

(16) Consists of warrants to purchase 67,500 shares and options to purchase
     3,750 shares exercisable within 60 days.

(17) Consists of common stock underlying warrants to purchase 67,500 shares.



                              PLAN OF DISTRIBUTION

     The shares of common stock may be sold from time to time by the selling
stockholders and their successors, including their transferees, pledgees or
donees or their respective successors. Such sales may be made on one or more
exchanges or in the over-the-counter market, or otherwise at prices and at terms
then prevailing or at prices related to the then-current market price, or in
negotiated transactions.

     The shares of common stock may be sold by selling stockholders in one or
more of the following types of transactions:

                                        8


     o    a block trade in which the broker or dealer so engaged 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 such broker
          or dealer for its account pursuant to the resale registration
          statement;

     o    an exchange distribution in accordance with the rules of such
          exchange;

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

     o    transactions between sellers and purchasers without a broker/dealer.

     In addition, any securities covered by the registration statement of which
this prospectus is a part that qualify for sale pursuant to Rule 144 may be sold
under Rule 144 rather than pursuant to the registration statement. From time to
time as permitted by law the selling stockholders may engage in short sales,
short sales versus the box, puts and calls and other transactions in securities
of the issuer or derivatives thereof, and may sell and deliver the shares of
common stock in connection therewith. In effecting sales, brokers or dealers
engaged by the selling stockholders may arrange for other brokers or dealers to
participate. Brokers or dealers will receive commissions or discounts from
selling stockholders in amounts to be negotiated immediately prior to the sale.

     The selling stockholders and any broker-dealers that act in connection with
the sale of common stock under this prospectus may be deemed to be
"underwriters" within the meaning of Section 2(11) of the Securities Act and any
commissions received and any profit on the resale of the common stock may be
deemed to be underwriting discounts or commissions under the Securities Act.
Neither we nor any selling stockholder can presently estimate the amount of such
compensation. Selling stockholders and broker-dealers who are "underwriters"
within the meaning of the Securities Act are subject to the prospectus delivery
requirements of the Securities Act.

     To the extent required, the specific common stock to be sold, the names of
the selling stockholders, the respective purchase prices and public offering
prices, the names of any agent, dealer or underwriter, and any applicable
discounts, concessions or commissions with respect to a particular offer will be
set forth in an amendment to the registration statement, of which this
prospectus is a part, or in a supplement to this prospectus, as required by law.

     We have agreed, among other things, to bear all fees and expenses in
connection with the sale of the securities being registered hereby (except any
underwriting discounts and commissions and expenses incurred by the selling
stockholders for brokerage, accounting, tax or legal services or other expenses
incurred by the selling stockholders in disposing of the securities being
registered hereby).

                                  LEGAL MATTERS

     The validity of the securities in respect of which this prospectus is being
delivered will be passed on for us by Wiggin and Dana LLP, Stamford,
Connecticut.

                                     EXPERTS

     The consolidated financial statements of CAS Medical Systems, Inc. as of
December 31, 2005 and 2004 and for the years then ended audited by UHY LLP,
independent registered public accounting

                                        9


firm, have been incorporated by reference herein and in the registration
statement in reliance upon the report thereon dated March 6, 2006 of said firm,
given upon its authority as experts in accounting and auditing.


                       WHERE YOU CAN FIND MORE INFORMATION

     We file annual, quarterly and current reports, proxy statements and other
information with the Securities and Exchange Commission under the Exchange Act.
You may read and copy any reports, statements or other information on file at
the Securities and Exchange Commission public reference room located at 100 F
Street N.E., Washington, D.C. 20549. Please call the Securities and Exchange
Commission at 1-800-SEC-0330 for further information on the public reference
room. Securities and Exchange Commission filings are also available to the
public from commercial document retrieval services. These filings are also
available at the Internet website maintained by the Securities and Exchange
Commission at http://www.sec.gov.

     We incorporate by reference into this prospectus the documents listed below
and any future filings we make with the Securities and Exchange Commission
pursuant to Section 13(a), 13(c), 14 or 15(d) of the Exchange Act, provided,
however, that we are not incorporating any information furnished under Items
2.02 or 7.01 of any current report on Form 8-K. Any statement in a document
incorporated by reference into this prospectus will be deemed to be modified or
superseded to the extent a statement contained in (1) this prospectus or (2) any
other subsequently filed document that is incorporated by reference into this
prospectus modifies or supersedes such statement.

     o    Current Reports on Form 8-K filed on March 6, 2006 and May 3, 2006;

     o    Quarterly Report on Form 10-QSB for the quarter ended March 31, 2006;

     o    Annual Report on Form 10-KSB for the year ended December 31, 2005;

     o    Definitive Proxy Statement filed April 24, 2006; and

     o    the description of our common stock contained in the Registration
          Statement on Form S-18 filed on March 7, 1985.

     Documents incorporated by reference are available without charge by
requesting them in writing or by telephone at:

                            CAS Medical Systems, Inc.
                               Investor Relations
                             44 East Industrial Road
                           Branford, Connecticut 06405
                                 (203) 488-6056


                 INDEMNIFICATION FOR SECURITIES ACT LIABILITIES

     Section 145 of the Delaware General Corporation Law provides that a
corporation may indemnify directors and officers as well as other employees and
individuals against expenses (including attorneys' fees), judgments, fines and
amounts paid in settlement actually and reasonably incurred by such person in
connection with any threatened, pending or completed actions, suits or
proceedings in which such person is made a party by reason of such person being
or having been a director, officer, employee or agent to the

                                       10


Registrant. The Delaware General Corporation Law provides that Section 145 is
not exclusive of other rights to which those seeking indemnification may be
entitled under any bylaw, agreement, vote of stockholders or disinterested
directors or otherwise. Article 5.2(a) of our certificate of incorporation and
Article XII of our bylaws provide for indemnification by us of our directors,
officers, employees and agents to the fullest extent permitted by the Delaware
General Corporation Law.

     Section 102(b)(7) of the Delaware General Corporation Law permits a
corporation to provide in its certificate of incorporation that a director of
the corporation shall not be personally liable to the corporation or its
stockholders for monetary damages for breach of fiduciary duty as a director,
except for liability (i) for any breach of the director's duty of loyalty to the
corporation or its stockholders, (ii) for acts or omissions not in good faith or
which involve intentional misconduct or a knowing violation of law, (iii) for
unlawful payments of dividends or unlawful stock repurchases, redemptions or
other distributions, or (iv) for any transaction from which the director derived
an improper personal benefit. Our certificate of incorporation provides for such
limitation of liability.

     We maintain standard policies of insurance under which coverage is provided
to our directors and officers against loss arising from claims made by reason of
breach of duty or other wrongful act.

     The foregoing indemnity provisions could require indemnification with
respect to liabilities arising under the Securities Act of 1933 (the "Act").
Insofar as indemnification for liabilities arising under the 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 Securities and Exchange Commission such indemnification is against public
policy as expressed in the Act and is, therefore, unenforceable.
















                                       11


                                     PART II

                     INFORMATION NOT REQUIRED IN PROSPECTUS

ITEM 14. OTHER EXPENSES OF ISSUANCE AND DISTRIBUTION

     The following table sets forth the costs and expenses, all of which will be
borne by the Registrant in connection with the sale of the securities being
registered hereby (except any underwriting discounts and commissions and
expenses incurred by the selling stockholders for brokerage, accounting, tax or
legal services or other expenses incurred by the selling stockholders in
disposing of the securities being registered hereby). All amounts are estimates
except the registration fee.

     SEC registration fee......................................   $    876.40
     Printing expenses.........................................   $  2,000.00
     Legal fees and expenses of the Registrant.................   $ 10,000.00
     Accounting fees and expenses..............................   $ 10,000.00
     Miscellaneous expenses....................................   $    123.60
                                                                  -----------
             Total.............................................   $ 23,000.00
                                                                  ===========

ITEM 15. INDEMNIFICATION OF DIRECTORS AND OFFICERS

     Section 145 of the Delaware General Corporation Law provides that a
corporation may indemnify directors and officers as well as other employees and
individuals against expenses (including attorneys' fees), judgments, fines and
amounts paid in settlement actually and reasonably incurred by such person in
connection with any threatened, pending or completed actions, suits or
proceedings in which such person is made a party by reason of such person being
or having been a director, officer, employee or agent to the Registrant. The
Delaware General Corporation Law provides that Section 145 is not exclusive of
other rights to which those seeking indemnification may be entitled under any
bylaw, agreement, vote of stockholders or disinterested directors or otherwise.
Article 5.2(a) of the Registrant's certificate of incorporation and Article XII
of the Registrant's bylaws provide for indemnification by the Registrant of its
directors, officers, employees and agents to the fullest extent permitted by the
Delaware General Corporation Law.

     Section 102(b)(7) of the Delaware General Corporation Law permits a
corporation to provide in its certificate of incorporation that a director of
the corporation shall not be personally liable to the corporation or its
stockholders for monetary damages for breach of fiduciary duty as a director,
except for liability (i) for any breach of the director's duty of loyalty to the
corporation or its stockholders, (ii) for acts or omissions not in good faith or
which involve intentional misconduct or a knowing violation of law, (iii) for
unlawful payments of dividends or unlawful stock repurchases, redemptions or
other distributions, or (iv) for any transaction from which the director derived
an improper personal benefit. The Registrant's certificate of incorporation
provides for such limitation of liability.

     The Registrant maintains standard policies of insurance under which
coverage is provided to its directors and officers against loss arising from
claims made by reason of breach of duty or other wrongful act.


                                      II-1


ITEM 16. EXHIBITS


EXHIBIT NUMBER        DOCUMENT
--------------        --------
5.1                   Opinion of Wiggin and Dana LLP
23.1                  Consent of Independent Registered Public Accounting Firm
23.2                  Consent of Wiggin and Dana LLP (included in the opinion
                      filed as Exhibit 5.1)
24.1                  Power of Attorney*




*  Previously filed.




























                                      II-2


ITEM 17. UNDERTAKINGS.

     (a) 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 small business issuers do not need to
               give the statements in paragraphs (a)(1)(i), (a)(1)(ii), and
               (a)(1)(iii) above if the information required in a post-effective
               amendment is incorporated by reference from periodic reports
               filed by the small business issuer under the Exchange Act of
               1934, or is contained in a form of prospectus filed pursuant to
               Securities Act Rule 424(b) that is deemed part of and included in
               the registration statement.

          (2) That, for determining liability under the Securities Act, each
post-effective amendment shall be treated as a new registration statement of the
securities offered, and the offering of the securities at that time shall be
treated as the initial BONA FIDE offering thereof.

          (3) To file a post-effective amendment to remove from registration any
of the securities that remain unsold at the end of this offering.

          (4) For determining liability of the undersigned small business issuer
under the Securities Act to any purchaser in the initial distribution of the
securities, the undersigned small business issuer undertakes that in a primary
offering of securities of the undersigned small business issuer 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 small
business issuer will be a seller to the purchaser and will be considered to
offer or sell such securities to such purchaser:

               (i)  Any preliminary prospectus or prospectus of the undersigned
                    small business issuer relating to the offering required to
                    be filed pursuant to Securities Act Rule 424;

                                      II-3


               (ii) Any free writing prospectus relating to the offering
                    prepared by or on behalf of the undersigned small business
                    issuer or used or referred to by the undersigned small
                    business issuer;

               (iii) The portion of any other free writing prospectus relating
                    to the offering containing material information about the
                    undersigned small business issuer or its securities provided
                    by or on behalf of the undersigned small business issuer;
                    and

               (iv) Any other communication that is an offer in the offering
                    made by the undersigned small business issuer to the
                    purchaser.

     (b) For determining any liability under the Securities Act, the undersigned
small business issuer will treat 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 small business issuer
under Rule 424(b)(1), or (4), or 497(h) under the Securities Act as part of this
registration statement as of the time the Commission declared it effective.

     (c) For determining any liability under the Securities Act, the undersigned
small business issuer will treat each post-effective amendment that contains a
form of prospectus as a new registration statement for the securities offered in
the registration statement, and that offering of the securities at that time as
the initial BONA FIDE offering of those securities.

     (d) For the purpose of determining liability under the Securities Act to
any purchaser, each prospectus filed pursuant to Securities Act Rule 424(b) as
part of a registration statement relating to an offering, other than
registration statements relying on Securities Act Rule 430B or other than
prospectuses filed in reliance on Securities Act Rule 430A, shall be deemed to
be part of and included in the registration statement as of the date it is first
used after effectiveness. 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 first use,
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 date of first use.

     (e) 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 (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-4


                                   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 Branford, State of Connecticut, on the 21st day of
July, 2006.



                                    CAS MEDICAL SYSTEMS INC.


                                    By: /s/ Louis P. Scheps
                                        ------------------------------
                                    Name: Louis P. Scheps
                                    Title: President and Chief Executive Officer



     Pursuant to the requirements of the Securities Act of 1933, this
Registration Statement has been signed by the following persons in the
capacities indicated on the 21st day of July, 2006.


SIGNATURE                                       TITLE
---------                                       -----

/s/ Louis P. Scheps             President, Chief Executive Officer and Director
--------------------------      (Principal Executive Officer)
(Louis P. Scheps)


/s/ Jeffery A. Baird            Chief Financial Officer
--------------------------      (Principal Financial and Accounting Officer)
(Jeffery A. Baird)


                                Director
--------------------------
(Lawrence S. Burstein)


/s/ Jerome S. Baron*            Director
--------------------------
(Jerome S. Baron)


/s/ Saul S. Milles*             Director
--------------------------
(Saul S. Milles)


*By: /s/ Jeffery A. Baird
     ---------------------
Jeffery A. Baird
Attorney-in-Fact

                                      II-5