<PAGE>


                      SECURITIES AND EXCHANGE COMMISSION

                            WASHINGTON, D.C.  20549
                                 ____________

                                  FORM 10-K/A

                       AMENDMENT NO. 1 TO ANNUAL REPORT
                    PURSUANT TO SECTIONS 13 OR 15(d) OF THE
                        SECURITIES EXCHANGE ACT OF 1934

                     For the year ended December 31, 1999


                         Commission File No. 000-21001

                               NMT MEDICAL, INC.
            (Exact Name of Registrant as Specified in its Charter)

            Delaware                                            95-4090463
-------------------------------                             -------------------
(State or Other Jurisdiction of                             (I.R.S. Employer
Incorporation or Organization)                              Identification No.)


       27 Wormwood Street, Boston, Massachusetts                   02210
------------------------------------------------             ------------------
  (Address of Principal Executive Offices)                       (Zip Code)

      Registrant's telephone number, including area code:  (617) 737-0930

          SECURITIES REGISTERED PURSUANT TO SECTION 12(B) OF THE ACT:
                                     None

          SECURITIES REGISTERED PURSUANT TO SECTION 12(G) OF THE ACT:
                    Common Stock, $.001 par value per share
                               (Title of Class)

Indicate by check mark whether the registrant:  (1) has filed all reports
required to be filed by Section 13 or 15(d) of the Securities Exchange Act of
1934 during the preceding 12 months (or for such shorter period that the
registrant was required to file such reports), and (2) has been subject to such
filing requirements for the past 90 days.    Yes   [X]       No [_]

Indicate by check mark if disclosure of delinquent filers pursuant to Item 405
of Regulation S-K is not contained herein, and will not be contained, to the
best of registrant's knowledge, in definitive proxy or information statements
incorporated by reference in Part III of this Form 10-K or any amendment to this
Form 10-K.  [_]

The aggregate market value of voting stock held by nonaffiliates of the
registrant on April 7, 2000 was $30,536,363, based on the last reported sale
price of the registrant's Common Stock on the Nasdaq National Market on that
date.  There were 10,908,421 shares of Common Stock outstanding as of April 7,
2000.
<PAGE>

     NMT Medical, Inc., a Delaware corporation (the "Registrant" or the
"Company"), hereby amends its Annual Report on Form 10-K with this Amendment No.
1 pursuant to Rule 12b-15 promulgated under the Securities Exchange Act of 1934,
as amended.


                                   PART III

ITEM 10.  DIRECTORS AND EXECUTIVE OFFICERS OF THE REGISTRANT

DIRECTORS

     Set forth below for each director are his name and age, his position(s)
with the Company, his principal occupation and business experience during the
past five years, and, where applicable, the year of his first election as a
director of the Company:

     MORRIS SIMON, M.D., age 74, a co-founder of the Company, has been a
director and the Scientific Director of the Company since 1986. Dr. Simon
currently provides consulting services to the Company. Since 1973, Dr. Simon has
been a Chairman and Director of Clinical Radiology at Boston's Beth Israel
Hospital, now Beth Israel Deaconess Medical Center. Since 1976, he has been a
Professor of Radiology at Harvard Medical School and in 1997 became Professor
Emeritus. The Company is an outgrowth of his pioneering research on the medical
potential of the thermal shape-memory alloy, nitinol, initiated in his
laboratory at Beth Israel Hospital.

     C. LEONARD GORDON, age 70, was appointed Acting President and Chief
Executive Officer of the Company in April 2000.  A co-founder of the Company,
Mr. Gordon served as the Company's Chief Executive Officer and President, from
August 1990 to January 1996 and as Chairman of the Board from January 1996 until
January 1998. Mr. Gordon has served as a director of the Company since its
inception in 1986. Mr. Gordon has been engaged in venture capital enterprises
for more than 10 years, particularly in the field of new medical technologies
and devices. He was co-founder and Chief Executive Officer of (i) Oxigene, Inc.
a publicly-traded company engaged in the design and development of drugs and
(ii) Biofield Corp., a publicly-traded medical device company that has developed
a breast cancer detection system. Mr. Gordon served as Chairman of the Board and
Chief Executive Officer of Immunotherapy Inc., a privately-held biotechnology
company and as President and Chief Executive Officer of Vacold LLC, a
developmental biotechnology company.

     R. JOHN FLETCHER, age 54, was elected a director of the Company in January
1996. Mr. Fletcher is the founder and Chief Executive Officer of Fletcher
Spaght, Inc., a management consulting company which specializes in strategic
development for health care and high technology businesses ("Fletcher Spaght").
Prior to founding Fletcher Spaght, Inc. in 1983, he was a senior member of The
Boston Consulting Group, a management consulting company. From April 1995 to
February 1996, Mr. Fletcher was the Chairman of the Board of InnerVentions,
Inc., a wholly-owned subsidiary of Fletcher Spaght, Inc. ("InnerVentions") which
the Company acquired in February 1996. Mr. Fletcher is a director of AutoImmune,
Inc., a biotechnology company developing orally administered pharmaceutical
products and Fischer Imaging Corporation, a medical device company.

     JEFFREY R. JAY, M.D., age 41, has been a director of the Company since
March 1996 and served as Chairman of the Board since 1998. Since September 1993,
he has been a General Partner of J.H. Whitney & Co., a venture capital
investment partnership. Dr. Jay is also a director of Advance Paradigm, Inc.,
a pharmaceutical benefits manager.

     JEFFREY F. THOMPSON, age 40, has been a director of the Company since June
1999.  Mr. Thompson has been Vice President of J.H. Whitney & Co., a venture
capital investment partnership, since August 1998.  From 1981 until joining
J.H. Whitney & Co., Mr. Thompson worked in various aspects of commercial
banking, most recently as a Senior Vice President of Transamerica Business
Credit Corp., a financial services company, from March 1997 to August 1998.
From September 1996 to March 1997, Mr. Thompson served as Manager for NYNEX
Credit Corp., a financial services company. From January 1992 to October 1995,
Mr. Thompson served as Vice President for Heller Financial, Inc., a financial
services company.

     ROBERT A. VAN TASSEL, M.D., age 61, has been a director of the Company
since March 1997. Dr. Van Tassel is a Board-certified cardiologist and has been
practicing as a consulting cardiologist at the Minneapolis Heart Institute at
Abbott Northwestern Hospital in Minneapolis since 1970. He is currently Chairman
of the Abbott Northwestern Hospital Cardiovascular Services Division and a
member of the Board of Directors of both Abbott Northwestern Hospital and
Medical Health Plan. Dr. Van Tassel has also served as a Clinical Professor of
Medicine at the University of Minnesota since 1972. In addition, Dr. Van Tassel
was a founder of the Minneapolis Heart Institute and past President of the
Institute's Foundation. Dr. Van Tassel was also a founder of AngioMedics Inc.,
a medical device company which was purchased by Pfizer Corporation in 1986.
Dr. Van Tassel is also a director of Boston Advanced Technologies, Inc., a high-
tech company producing precision sensor technology, AngioMedics II, a medical
technology company, Illuminex, a start-up company in the field of restenosis,
and ProMedicus, a medical information company. He is a Principal in TriCardia,
LLC, a life sciences consulting company.

                                       2
<PAGE>

     In connection with the acquisition by the Company of the CardioSEAL Septal
Occluder technology in 1996 from InnerVentions, the Company agreed to use its
best efforts to nominate a designee of Fletcher Spaght as a director of the
Company, and certain of the Company's stockholders agreed to vote their shares
of Common Stock in favor of such designee. Fletcher Spaght's designee, R. John
Fletcher, the founder and Chief Executive Officer of Fletcher Spaght, was first
elected to the Board of Directors of the Company in January 1996 and has served
on the Board of Directors of the Company since that time.

     In connection with the Company's 1996 preferred stock financing, in which
Whitney Equity Partners, L.P. ("Equity Partners") purchased 1,829,010 shares
(on a common stock equivalent basis) of the Company's capital stock, certain of
the Company's stockholders agreed to vote their shares of Common Stock in favor
of two Board designees of Equity Partners. Equity Partners' designees are
Jeffrey R. Jay, M.D. and Jeffrey F. Thompson. Dr. Jay was initially elected to
the Board of Directors of the Company in March 1996 and has served on the Board
of Directors of the Company since that time. Mr. Thompson was initially elected
to the Board of Directors of the Company in June 1999 and has served on the
Board of Directors of the Company since that time.

     There are no family relationships among any of the executive officers and
director nominees of the Company.

EXECUTIVE OFFICERS OF THE COMPANY

     The executive officers of the Company are elected on an annual basis and
serve at the discretion of the Board of Directors. The executive officers of the
Company and their ages as of April 11, 2000 are as follows:

<TABLE>
<CAPTION>
NAME                               AGE     POSITION
----                               ---     --------
<S>                              <C>       <C>
C. Leonard Gordon                  70      Acting President, Chief Executive
                                           Officer and Director
David A. Chazanovitz               49      President, NMT Neurosciences Division
William J. Knight                  50      Vice President of Finance and
                                           Administration, Chief Financial
                                           Officer, Secretary and Treasurer
</TABLE>

     C. LEONARD GORDON was appointed Acting President and Chief Executive
Officer of NMT in April 2000.  A co-founder of the Company, Mr. Gordon served as
the Company's Chief Executive Officer and President, from August 1990 to January
1996 and as Chairman of the Board from January 1996 until January 1998. Mr.
Gordon has served as a director of the Company since its inception in 1986. Mr.
Gordon has been engaged in venture capital enterprises for more than 10 years,
particularly in the field of new medical technologies and devices. He was co-
founder and Chief Executive Officer of (i) Oxigene, Inc. a publicly-traded
company engaged in the design and development of drugs and (ii) Biofield Corp.,
a publicly-traded medical device company that has developed a breast cancer
detection system. Mr. Gordon served as Chairman of the Board and Chief Executive
Officer of Immunotherapy Inc., a privately-held biotechnology company and as
President and Chief Executive Officer of Vacold LLC, a developmental
biotechnology company.

     DAVID A. CHAZANOVITZ has served as President, NMT Neurosciences Division
since July 1998.  From January 1996 to July 1998, Mr. Chazanovitz served as
President of NMT's Septal Repair Division.  Prior to joining the Company,
Mr. Chazanovitz served as President and Chief Executive Officer of InnerVentions
from April 1995 until January 1996. Mr. Chazanovitz was employed by Bard from
1979 to 1995 in various positions including President of the USCI Angiography
Division, Bard Electrophysiology Division and Bard Ventures Division where he
was a founder. During his last two and one-half years at Bard, Mr. Chazanovitz
had overall responsibility for the septal defect repair program.

     WILLIAM J. KNIGHT has served as Vice President of Finance and
Administration and Chief Financial Officer since September 1998.  From August
1996 until September 1998, Mr. Knight held the position of Vice President
Administration and Chief Financial Officer of Zoll Medical Corporation, a
medical device manufacturer.  From September 1989 to February 1996, Mr. Knight
was Vice President, Corporate Controller of Analytical Technology, Inc., a
manufacturer of scientific instrumentation, which was acquired by ThermoElectron
Corporation in December 1995.

SECTION 16(A) BENEFICIAL OWNERSHIP REPORTING COMPLIANCE

     Section 16(a) of the Securities Exchange Act of 1934, as amended, requires
the Company's directors, executive officers and holders of more than 10% of the
outstanding shares of Common Stock to file with the Securities and Exchange
Commission initial reports of ownership and reports of changes in ownership of
Common Stock and other equity securities of the Company. Except as described
below, and based solely upon a review of reports submitted, and representations
made, to the Company, the Company believes that during 1999 its executive
officers, directors and holders of more than 10% of the outstanding shares of
Common Stock complied with all Section 16(a) filing requirements.

                                       3
<PAGE>

     In July 1999, R. John Fletcher, a director of the Company, filed an Annual
Statement of Changes in Beneficial Ownership to report the grant of stock
options to purchase 2,500 shares of Common Stock at an exercise price of $6.31
per share on June 3, 1998.

     In July 1999, C. Leonard Gordon, the Acting President and Chief Executive
Officer and a director of the Company, filed a Statement of Changes in
Beneficial Ownership to report the exercise of stock options to purchase 65,788
shares of Common Stock at an exercise price of $1.14 per share on March 26,
1999. In November 1999, Mr. Gordon filed a Statement of Changes in Beneficial
Ownership to report his purchase of 5,500 shares of Common Stock at a purchase
price of $2.74 per share on September 29, 1999.

     In February 2000, Jeffrey R. Jay, M.D., the Chairman of the Board of
Directors of the Company, filed an Annual Statement of Changes in Beneficial
Ownership to report the grant of stock options to purchase 2,500 shares of
Common Stock at an exercise price of $6.31 per share on June 3, 1998.


ITEM 11.  EXECUTIVE COMPENSATION

COMPENSATION COMMITTEE INTERLOCKS AND INSIDER PARTICIPATION

     The Company's Compensation Committee is comprised of three members,
including two of the Company's non-employee directors. The current members are
Mr. Gordon and Dr. Jay.  Mr. Tully, the Company's former President and Chief
Executive Officer, also served on the Compensation Committee until his
resignation from the Board of Directors on April 8, 2000.  No executive officer
of the Company has served as a director or member of the compensation committee
(or other committee serving an equivalent function) of any other entity, whose
executive officers served as a director or member of the Compensation Committee
of the Company.

DIRECTOR COMPENSATION

     Beginning in January 2000, each non-employee director of the Company, not
otherwise compensated by the Company, receives a fee of $2,000 for attendance in
person at each Board meeting.  Prior to January 2000, each non-employee director
not otherwise compensated by the Company received a fee of $1,000 for attendance
in person at each Board meeting.  All directors receive reimbursement of travel
expenses incurred in connection with their attendance at Board and Committee
meetings.

     In 1996, the Board of Directors adopted, and the stockholders approved, the
1996 Stock Option Plan for Non-Employee Directors (the "1996 Directors' Stock
Plan"), which provides for the issuance of a maximum of 150,000 shares of Common
Stock. On the effective date of the 1996 Directors' Stock Plan, each non-
employee director of the Company who did not otherwise receive compensation from
the Company received an option to purchase 10,000 shares of Common Stock. In
addition, the 1996 Directors' Stock Plan also provides for an initial option
grant to purchase 10,000 shares of Common Stock to each new non-employee
director upon his or her initial election to the Board of Directors. These
options vest in equal monthly installments over a three-year period. In addition
to this initial grant, the 1996 Directors' Stock Plan provides for annual grants
of stock options to purchase 2,500 shares of Common Stock to each eligible
director, other than to a director who receives an initial grant of options in
the same year. These options become fully vested six months after the date of
grant. The exercise price of options granted under the 1996 Directors' Stock
Plan will equal the fair market value of the Common Stock on the date of grant.
In the event an optionee ceases to serve as a director, each option may be
exercised by the optionee for the portion then exercisable at any time within
one year after the optionee ceases to serve as a director of the Company.

                                       4
<PAGE>

EXECUTIVE COMPENSATION

                          SUMMARY COMPENSATION TABLE

     The following table sets forth certain information concerning the
compensation for each of the last three fiscal years for the Company's Chief
Executive Officer and its two other most highly compensated executive officers
whose total annual salary and bonus exceeded $100,000 in the fiscal year ended
December 31, 1999 (collectively, the "Named Executives").

<TABLE>
<CAPTION>
                                                  ANNUAL            LONG-TERM COMPENSATION
                                               COMPENSATION                 AWARDS
                                       --------------------------   ----------------------
                                                                     NUMBER OF SECURITIES
                                                SALARY     BONUS       UNDERLYING STOCK            ALL OTHER
NAME AND PRINCIPAL POSITION              YEAR     ($)       ($)        OPTIONS (#)(1)(2)      COMPENSATION ($)(3)
---------------------------              ----  ---------  -------   ---------------------     -------------------
<S>                                      <C>   <C>        <C>       <C>                      <C>
Thomas M. Tully........................  1999  $292,614   $11,666           100,000                  $  --
 Former President and Chief Executive    1998   249,760        --             3,225                     --
 Officer(4)                              1997   216,426    57,500      (ITC) 50,000                     --

David A. Chazanovitz...................  1999   191,946        --                --                     --
 President, NMT Neurosciences            1998   196,410        --             3,225                     --
 Division                                1997   171,085    19,000            15,000                     --

William J. Knight......................  1999   160,414     9,000            16,750                     --
 Vice President-Finance and              1998    42,000    20,000            51,000                     --
 Administration, Chief Financial
 Officer(5)
</TABLE>
__________

(1)  The Company has never granted any stock appreciation rights.
(2)  In addition to receiving options to purchase Common Stock of the Company,
     certain of the Named Executives have been granted options to purchase
     Common Stock of Image Technologies Corporation, an affiliate of the Company
     (designated in the table as "ITC"), as compensation for service to ITC in
     capacities other than as an executive officer of the Company. The options
     vest in four equal annual installments commencing on the date of grant.
     The vesting of these options is subject to acceleration in the event of any
     change of control of ITC.
(3)  In accordance with the rules of the Securities and Exchange Commission,
     other compensation in the form of perquisites and other personal benefits
     has been omitted in those instances where such perquisites and other
     personal benefits constituted less than the lesser of $50,000 or ten
     percent of the total of annual salary and bonus for the Named Executives
     for the fiscal year.
(4)  Mr. Tully resigned as President and Chief Executive Officer and as a member
     of the Board of Directors of the Company on April 8, 2000.  Mr. Tully
     continues to perform certain services for the Company as a part-time
     employee.
(5)  The 1998 bonus was paid to Mr. Knight as a signing bonus upon his
     commencement of employment with the Company in September 1998.  Mr. Knight
     was granted an option to purchase 16,750 shares of Common Stock in February
     2000 as a 1999 bonus.


                       OPTION GRANTS IN LAST FISCAL YEAR

  The following table sets forth certain information concerning grants of stock
options made during the year ended December 31, 1999 to each of the Named
Executives.

<TABLE>
<CAPTION>
                                                         INDIVIDUAL GRANTS
                                        -------------------------------------------------------
                                                        PERCENTAGE                                POTENTIAL REALIZABLE
                                                         OF TOTAL                                   VALUE AT ASSUMED
                                         NUMBER OF       OPTIONS                                 ANNUAL RATES OF STOCK
                                        SECURITIES      GRANTED TO     EXERCISE OR               PRICE APPRECIATION FOR
                                        UNDERLYING      EMPLOYEES      BASE PRICE                    OPTION TERM(2)
                                          OPTIONS       IN FISCAL       PER SHARE    EXPIRATION  ---------------------
NAME                                    GRANTED (#)      YEAR (%)     ($/SHARE)(1)      DATE       5%($)       10%($)
----                                    -----------     ---------     ------------   ----------  --------     --------
<S>                                    <C>          <C>           <C>              <C>         <C>            <C>
Thomas M. Tully......................     100,000         35.5%         $4.38         1/19/09    $275,000     $698,000
David A. Chazanovitz.................          --           --             --              --          --           --
William J. Knight(3).................          --           --             --              --          --           --
</TABLE>
__________
(1)  The exercise price is equal to the fair market value of the Company's
     Common Stock on the date of grant.

                                       5
<PAGE>

(2)  Amounts represent hypothetical gains that could be achieved for the
     respective options if exercised at the end of the option term. These gains
     are based on assumed rates of stock appreciation of 5% and 10% compounded
     annually from the date the respective options were granted to their
     expiration date. The gains shown are net of the option exercise price, but
     do not include deductions for taxes or other expenses associated with the
     exercise of the option or the sale of the underlying shares. Actual gains,
     if any, on stock option exercises will depend on the future performance of
     the Common Stock, the option holder's continued employment through the
     option period and the date on which the options are exercised.
(3)  Excludes Mr. Knight's option to purchase 16,750 shares of Common Stock
     which was granted in February 2000 as a 1999 bonus.


                  AGGREGATED OPTION EXERCISES IN LAST FISCAL
                    YEAR AND FISCAL YEAR-END OPTION VALUES

   The following table sets forth, for each Named Executive, the number of
shares of Common Stock acquired upon exercise of options during the fiscal year
ended December 31, 1999, the aggregate dollar value realized upon such exercise
and the number and value of unexercised options held by each Named Executive on
December 31, 1999.


<TABLE>
<CAPTION>

                                           NUMBER OF
                                            SHARES
                                           ACQUIRED
                                              ON        VALUE             NUMBER OF SECURITIES              VALUE OF UNEXERCISED
                                           EXERCISE    REALIZED          UNDERLYING UNEXERCISED           IN-THE-MONEY OPTIONS AT
NAME                                          (#)       ($)(1)       OPTIONS AT DECEMBER 31, 1999(#)      DECEMBER 31, 1999 ($)(2)
----                                       --------    --------      -------------------------------     ---------------------------
                                                                     EXERCISABLE       UNEXERCISABLE     EXERCISABLE   UNEXERCISABLE
                                                                     -----------       -------------     -----------   -------------
<S>                                        <C>         <C>           <C>             <C>              <C>              <C>
Thomas M. Tully(3)...................         --       $   --           412,815          110,000         $192,105         $     --
David A. Chazanovitz(4)..............         --           --           104,409           33,289           57,439           11,526
William J. Knight(5).................         --           --            13,500           37,500               --               --
</TABLE>
__________
(1)  Represents the difference between the exercise price and the fair market
     value of the Common Stock on the date of exercise.
(2)  Represents the difference between the last reported sale price per share of
     the Common Stock on December 31, 1999 ($2.875 per share), as reported on
     the Nasdaq National Market, and the option exercise price, multiplied by
     the number of shares underlying the options.
(3)  Exercisable includes options to purchase 263,157 shares at an exercise
     price of $2.15 per share, 116,433 shares at $6.95 per share, 30,000 shares
     at $10.00 per share and 3,225 shares at $4.56 per share. Unexercisable
     includes options to purchase 10,000 shares at an exercise price of $10.00
     per share and 100,000 shares at $4.38 per share.
(4)  Exercisable includes options to purchase 78,684 shares at an exercise price
     of $2.15 per share, 18,750 shares at $10.00 per share, 3,750 shares at
     $7.38 per share and 3,225 shares at $4.56 per share. Unexercisable includes
     options to purchase 15,789 shares at an exercise price of $2.15 per share,
     6,250 shares at $10.00 per share and 11,250 shares at $7.38 per share.
(5)  Exercisable includes options to purchase 12,500 shares at an exercise price
     of $4.25 per share and 1,000 shares at $4.56 per share.  Unexercisable
     consists of options to purchase 37,500 shares at an exercise price of $4.25
     per share.

EMPLOYMENT AND SEVERANCE AGREEMENTS

     Effective January 1, 1999, the Company entered into a three-year employment
agreement with Thomas M. Tully, then the Company's President and Chief Executive
Officer. Pursuant to this agreement, Mr. Tully received a salary of $292,200 in
1999. In addition, in connection with the execution of his employment agreement,
the Company granted Mr. Tully stock options to purchase an aggregate of 100,000
shares of the Company's Common Stock (the "Options") at an exercise price of
$4.38 per share and paid Mr. Tully a bonus of $11,666. The Options will, to the
maximum extent permissible under Section 422 of the Internal Revenue Code of
1986, as amended (the "Code"), constitute incentive stock options, with any
balance of the Options to be treated as non-statutory options. The Options vest
in four equal annual installments on the first, second, third and fourth
anniversaries of the grant date. Mr. Tully resigned from his position as
President and Chief Executive Officer of the Company on April 8, 2000. Pursuant
to the terms of the employment agreement, the Company will pay Mr. Tully
severance equal to twelve months salary. In order to assist the Company with
respect to management transition and several on-going marketing, litigation and
other business issues, Mr. Tully has entered into a one-year employment
agreement with the Company, commencing April 8, 2000. Mr. Tully will receive an
annual salary of $25,000. During the term of this employment agreement, Mr.
Tully's stock options will continue to vest. All exercisable Options held by Mr.
Tully will expire three months after such termination of his employment. Mr.
Tully has agreed not to compete with the Company for a period of one year after
he ceases to be employed by the Company.

                                       6
<PAGE>

     Effective July 1, 1998, the Company entered into a two-year employment
agreement with David A. Chazanovitz, the President of the Company's NMT
Neurosciences Division. Pursuant to this agreement, Mr. Chazanovitz currently
receives a salary of $205,000 per year. In addition, the Company agreed to pay
Mr. Chazanovitz additional cash compensation for extraordinary costs
attributable to Mr. Chazanovitz's assignment in France. Mr. Chazanovitz has
agreed not to compete with the Company for a period of one year after he ceases
to be employed by the Company.

REPORT OF THE COMPENSATION COMMITTEE AND STOCK OPTION COMMITTEE

     The Compensation Committee and the Stock Option Committee of the Company's
Board of Directors, are responsible for establishing compensation policies with
respect to the Company's executive officers, including the Chief Executive
Officer and the other executive officers named in the Summary Compensation
Table, and setting the compensation for these individuals.  Until April 2000
when Mr. Tully resigned as President and Chief Executive Officer and a director
of the Company and Mr. Gordon, a non-employee director of the Company, was
appointed Acting President and Chief Executive Officer of the Company, the
Compensation Committee was comprised of Mr. Tully and two non-employee
directors, Mr. Gordon and Dr. Jay.  When Mr. Tully resigned as a member of the
Board, he resigned as a member of the Compensation Committee.  The vacancy
created by Mr. Tully's resignation has not been filled.  The Stock Option
Committee is currently comprised of two non-employee directors, Mr. Fletcher and
Dr. Jay.

     The Company's executive compensation program is designed to maximize the
performance of the Company's executive officers and, thereby, to maximize the
Company's business goals and stockholder returns. Executive compensation
consists of a combination of base salary, annual cash bonuses and merit-based
stock incentives. The Compensation Committee considers merit-based stock
incentives, which are determined by the Stock Option Committee, to be a critical
component of an executive's compensation package for purposes of helping to
align that executive's interests with stockholder interests.

Compensation Philosophy

     The objectives of the executive compensation program are to align
compensation with business objectives and individual performance and to enable
the Company to attract, retain and reward executive officers who are expected to
contribute to the long-term success of the Company. The Company's executive
compensation philosophy is based on the principles of competitive and fair
compensation and sustained performance.

     .  COMPETITIVE AND FAIR COMPENSATION

        The Company is committed to providing an executive compensation program
        that helps attract and retain highly qualified executives. To ensure
        that compensation is competitive, the Company compares its compensation
        practices with those of similar companies in the industry and sets the
        Company's compensation guidelines based on this review. The Compensation
        Committee believes compensation for the Company's executive officers is
        within the range of compensation paid to executives with comparable
        qualifications, experience and responsibilities in the same or similar
        businesses and in companies of comparable size and success. The
        Compensation Committee also strives to achieve equitable relationships
        both among the compensation of individual officers and between the
        compensation of officers and other employees throughout the Company.

     .  SUSTAINED PERFORMANCE

        Executive officers are rewarded based upon corporate performance and
        individual performance. Corporate performance is evaluated by reviewing
        the extent to which strategic scientific and business plan goals are
        met, including such factors as meeting budgeted financial targets,
        continued innovation in the development of the Company's technologies
        and formation of new business alliances and acquisitions. Individual
        performance is evaluated by reviewing the attainment of specified
        individual objectives.

     In evaluating each executive officer's performance, the Compensation
Committee and the Stock Option Committee generally conform to the following
process:

     .  Company and individual goals and objectives are set at the beginning of
        the performance cycle.

     .  At the end of the performance cycle, the accomplishment of the
        executive's goals and objectives and his contributions to the Company
        are evaluated and communicated to the executive.

                                       7
<PAGE>

     .  The results, combined with comparative compensation practices of other
        companies in the industry, are then used to review base salary levels
        and to determine cash bonuses and stock compensation awards.

     Annual compensation for the Company's executives generally consists of
three elements - base salary, cash bonuses and stock options.

     Base salaries of the Company's executives are generally set by reviewing
compensation for competitive positions in the market and the historical
compensation levels of the particular executive. Payment of bonus awards is
based on the Company's financial performance as well as on individual
performance measured against targeted performance and various additional
performance criteria. Seventy-five percent of each executive's bonus
compensation is objectively determined and based upon the Company's achievement
of financial goals established by the Board of Directors. The remaining twenty-
five percent of each executive's bonus compensation is subjectively determined
based upon targeted performance criteria which varies for each executive based
on his area of responsibility. Subjective performance criteria include an
executive's ability to motivate others, develop the skills necessary to grow as
the Company matures, recognize and pursue new business opportunities and
initiate programs to enhance the Company's growth and success.  Based upon a
review of this criteria, the Compensation Committee approved a bonus payment to
Mr. Knight.

     Compensation at the executive officer level also includes the long-term
incentives afforded by stock options. The stock option program, which is
administered by the Stock Option Committee, is designed to align the long-term
interests of the Company's employees and its stockholders and to assist in the
retention of executives. The size of option grants is generally intended to
reflect the executive's position with the Company and his contributions to the
Company, including his success in achieving the individual performance criteria
described above. The option program generally uses a four-year vesting period to
encourage key employees to continue in the employ of the Company. When granting
stock options, it has generally been the policy of the Company to fix the
exercise price of such options at 100% of the fair market value of the Common
Stock on the date of grant. During 1999, all current executive officers received
options to purchase an aggregate of 100,000 shares of Common Stock, at a
weighted average exercise price of $4.38 per share.

Compliance with Internal Revenue Code Section 162(m)

     Section  of the Code, generally disallows a federal income tax deduction to
public companies for certain compensation in excess of $1.0 million paid to a
corporation's chief executive officer and any of its four other most highly
compensated executive officers. Qualifying performance-based compensation will
not be subject to the deduction limit if certain requirements are met. The
Company's 1996 Stock Option Plan and 1998 Equity Incentive Plan have been
structured to qualify income received upon the exercise of stock options granted
under such plans as qualifying performance-based compensation. The Company
intends to structure the performance-based portion of the compensation of its
executive officers in a manner that complies with the statute so as to mitigate
any disallowance of deductions.

Mr. Tully's 1999 Compensation

     Mr. Tully resigned as President and Chief Executive Officer of the Company
on April 8, 2000.  Pursuant to the terms of his three year employment agreement
with the Company, Mr. Tully's salary for 1999 increased to $292,200 from
$249,760 in 1998.  In connection with the signing of his employment contract,
which became effective on January 1, 1999, Mr. Tully also received options to
purchase 100,000 shares of Common Stock at an exercise price of $4.38 per share.
Mr. Tully did not participate in the Compensation Committee's discussion of his
1999 bonus compensation.

                              Compensation Committee

                              C. Leonard Gordon
                              Jeffrey R. Jay, M.D.

                              Stock Option Committee

                              R. John Fletcher
                              Jeffrey R. Jay, M.D.

                                       8
<PAGE>

STOCK PERFORMANCE GRAPH

     The following graph compares the cumulative total stockholder return on the
Common Stock of the Company from September 27, 1996 (the date the Company's
Common Stock was registered under the Securities Exchange Act of 1934, as
amended) through December 31, 1999 with the cumulative total return during this
period of (i) The Nasdaq Stock Market - U.S. Index and (ii) The S&P Health Care
(Medical Products and Supplies) Index. This graph assumes the investment of $100
on September 27, 1996 in the Company's Common Stock and in each of the indices
listed above, and assumes dividends are reinvested.


                              [GRAPH APPEARS HERE]


                            CUMULATIVE TOTAL RETURN
<TABLE>
                              9/27/1996  12/1996  12/1997   12/1998  12/1999
                              ---------  -------  -------   -------  -------
<S>                           <C>        <C>      <C>       <C>      <C>
NMT Medical, Inc.                100       114       73        34       26
Nasdaq
Stock Market-U.S. Index          100       113      138       195      352

S&P Health Care (Medical
Products and Supplies) Index     100       115      144       207      192
</TABLE>

ITEM 12.  SECURITY OWNERSHIP OF CERTAIN BENEFICIAL OWNERS AND MANAGEMENT

STOCK OWNERSHIP OF CERTAIN BENEFICIAL OWNERS AND MANAGEMENT

  The following table sets forth certain information as of January 31, 2000 with
respect to the beneficial ownership of the Common Stock by (i) each person known
by the Company to beneficially own more than 5% of the outstanding shares of
Common Stock, (ii) each director and nominee for director of the Company, (iii)
each executive officer of the Company named in the Summary Compensation Table
set forth under the caption "Executive Compensation" below and (iv) all
directors and executive officers of the Company as of January 31, 2000 as a
group:

<TABLE>
<CAPTION>
                                                                     PERCENTAGE
                                                      NUMBER OF          OF
                                                       SHARES       OUTSTANDING
                                                    BENEFICIALLY       COMMON
NAME AND ADDRESS OF BENEFICIAL OWNER (1)              OWNED(2)        STOCK(3)
----------------------------------------            ------------    -----------
<S>                                                <C>             <C>
Entities affiliated with J.H. Whitney & Co.(4)...     2,529,010          23.41%
   177 Broad Street
   Stamford, CT 06901
C. Leonard Gordon(5).............................       785,876           7.14%
State of Wisconsin Investment Board(6)...........       677,500           6.29%
   P.O. Box 7842
   Madison, WI  53707
Dimensional Fund Advisors Inc.(7)................       619,000           5.74%
   1299 Ocean Avenue, 11th Floor
   Santa Monica, CA  90401
Fletcher Spaght, Inc.(8).........................       587,352           5.41%
   222 Berkeley Street
   Boston, MA 02116-3761
Morris Simon, M.D.(9)............................       184,823           1.71%
   8 Otis Place
   Boston, MA 02108
R. John Fletcher(10).............................        17,500              *
   c/o Fletcher Spaght, Inc.
   222 Berkeley Street
   Boston, MA 02116-3761
</TABLE>

                                       9
<PAGE>

<TABLE>
<CAPTION>
                                                                     PERCENTAGE
                                                      NUMBER OF          OF
                                                       SHARES       OUTSTANDING
                                                    BENEFICIALLY       COMMON
NAME AND ADDRESS OF BENEFICIAL OWNER (1)              OWNED(2)        STOCK(3)
----------------------------------------            ------------    -----------
<S>                                                <C>             <C>
Jeffrey R. Jay, M.D.(11).........................        17,500              *
   c/o J.H. Whitney & Co.
   177 Broad Street
   Stamford, CT 06901
Robert A. Van Tassel, M.D.(12)...................        16,250              *
   c/o Minneapolis Cardiology Associates
   920 East 28th Street
   Minneapolis, MN 55047
Jeffrey F. Thompson(13)..........................         1,944              *
   c/o J.H. Whitney & Co.
   177 Broad Street
   Stamford, CT 06901
Thomas M. Tully(14)..............................       440,841           3.93%
David A. Chazanovitz(15).........................       160,595           1.47%
William J. Knight(16)............................        14,227              *
All current directors and executive
  officers of the Company as a
  group (9 persons)(17)..........................     1,639,556          14.04%
</TABLE>
_________________
 *   Less than 1%
(1)  Except as otherwise indicated, the address of each beneficial owner is c/o
     NMT Medical, Inc., 27 Wormwood Street, Boston, MA 02210-1625.
(2)  The number of shares of Common Stock beneficially owned by each director or
     executive officer is determined under the rules of the Securities and
     Exchange Commission, and the information is not necessarily indicative of
     beneficial ownership for any other purpose. Under such rules, beneficial
     ownership includes any shares as to which the individual has sole or shared
     voting power or investment power and also any shares which the individual
     has the right to acquire within 60 days after January 31, 2000 through the
     exercise of any stock option or other right. Unless otherwise indicated,
     each person has sole investment and voting power (or shares such power with
     his spouse) with respect to the shares set forth in the table. The
     inclusion herein of any shares deemed beneficially owned does not
     constitute an admission of beneficial ownership of those shares.
(3)  The number of shares deemed outstanding for purposes of calculating these
     percentages is comprised of the 10,779,890 shares of Common Stock
     outstanding on January 31, 2000, plus any shares of Common Stock issuable
     to the person in question within 60 days after January 31, 2000 upon
     exercise of stock options or any other rights held by such person.
(4)  The number of shares owned by J.H. Whitney & Co., a New York limited
     partnership ("Whitney"), and entities affiliated with Whitney, consists of
     1,829,010 shares held of record by Whitney Equity Partners, L.P., a
     Delaware limited partnership ("Equity Partners"), 561,207 shares held of
     record by Whitney Subordinated Debt Fund, L.P., a Delaware limited
     partnership ("Debt Fund"), and 113,793 shares held of record by Whitney.
     Also includes warrants to purchase 25,000 shares of Common Stock at an
     exercise price of $3.41 per share held by Whitney. Each of Whitney, Equity
     Partners and Debt Fund disclaims beneficial ownership of the shares held by
     the other two partnerships.  Excludes shares held of record by Mr. Thompson
     and Dr. Jay. See Notes 11 and 13.
(5)  Mr. Gordon's shares are all owned jointly with his wife, except for 25,500
     shares held in his wife's name.  Also includes 219,969 shares of Common
     Stock issuable to Mr. Gordon within 60 days after January 31, 2000 upon
     exercise of stock options.
(6)  This information is derived from a Schedule 13G filed with the Securities
     and Exchange Commission on February 2, 2000 by the State of Wisconsin
     Investment Board.
(7)  This information is derived from a Schedule 13G filed with the Securities
     and Exchange Commission on February 3, 2000.  Dimensional Fund Advisors
     Inc. ("Dimensional"), an investment advisor registered under Section 203 of
     the Investment Advisors Act of 1940, furnishes investment advice to four
     investment companies registered under the Investment Company Act of 1940,
     and serves as investment manager to certain other investment vehicles,
     including commingled group trusts (these investment companies and
     investment vehicles are the "Portfolios").  In its role as investment
     advisor and investment manager, Dimensional possesses both voting and
     investment power over 619,000 shares of Common Stock as of December 30,
     1999.  The Portfolios own all securities reported in this statement, and
     Dimensional disclaims beneficial ownership of such securities.
(8)  Consists of an aggregate of 504,023 shares and warrants to purchase 83,329
     shares of Common Stock at an exercise price of $2.15 per share held by
     Fletcher Spaght, Inc., of which Mr. Fletcher is the founder, Chief
     Executive Officer and a principal stockholder. Mr. Fletcher is a director
     of the Company.

                                       10
<PAGE>

(9)  Includes 39,472 shares of Common Stock issuable to Dr. Simon within 60 days
     after January 31, 2000 upon exercise of stock options.  Also includes
     26,315 shares which Dr. Simon owns jointly with his wife and 52,630 shares
     held in his name, Dr. Simon disclaims beneficial ownership of 66,406 shares
     owned by his wife.
(10) Consists of 17,500 shares of Common Stock issuable to Mr. Fletcher within
     60 days after January 31, 2000 upon exercise of stock options.
(11) Consists of 17,500 shares of Common Stock issuable to Dr. Jay within 60
     days after January 31, 2000 upon exercise of stock options. Dr. Jay is a
     managing member of J.H. Whitney Equity Partners, L.L.C., the general
     partner of Equity Partners, and a general partner of both Debt Fund and
     Whitney. Dr. Jay disclaims beneficial ownership of the shares held by
     Equity Partners, Debt Fund and Whitney, except to the extent of his
     proportionate pecuniary interests in these funds or these entities.
(12) Consists of 16,250 shares of Common Stock issuable to Dr. Van Tassel within
     60 days after January 31, 2000 upon exercise of stock options.
(13) Consists of 1,944 shares of Common Stock issuable to Mr. Thompson within 60
     days after January 31, 2000 upon exercise of stock options.  Mr. Thompson
     is Vice President of Whitney and disclaims beneficial ownership of the
     shares held by Whitney, Equity Partners and Debt Fund, except to the extent
     of his proportionate pecuniary interests in these funds or these entities.
(14) Includes 437,815 shares of Common Stock issuable to Mr. Tully within 60
     days after January 31, 2000 upon exercise of stock options. Mr. Tully
     resigned as President and Chief Executive Officer and a director on April
     8, 2000. Mr. Tully continues to perform certain services for the Company
     as a part-time employee.
(15) Includes 108,159 shares of Common Stock issuable to Mr. Chazanovitz within
     60 days after January 31, 2000 upon exercise of stock options and warrants
     to purchase 28,489 shares of Common Stock at an exercise price of $2.15 per
     share.
(16) Includes 13,500 shares of Common Stock issuable to Mr. Knight within 60
     days after January 31, 2000 upon exercise of stock options.
(17) Includes an aggregate of 900,598 shares of Common Stock issuable upon
     exercise of stock options and warrants held by all current directors and
     executive officers as of January 31, 2000 as a group which are exercisable
     within 60 days after January 31, 2000. Includes shares held by Mr. Tully.


ITEM 13.  CERTAIN RELATIONSHIPS AND RELATED TRANSACTIONS

  The Company's July 1998 acquisition of the neurosurgical instruments business
of Elekta AB (Publ), a Swedish corporation, was financed, in part, with a $20
million subordinated note issued to an affiliate of J.H. Whitney & Co., a
significant stockholder of the Company.  The subordinated note is due September
30, 2003 with quarterly interest payable at 10.101% per annum.  In September
1999, the principal amount of the subordinated note was reduced to $6 million.
In addition, in April 2000 the Company used a portion of the proceeds from its
sale of the U.K. operations and certain other assets of the NMT Neurosciences
division to further reduce the principal amount of the subordinated note payable
by $500,000 to $5.5 million.

  In April 1987, the Company entered into a Technology Purchase Agreement with
Morris Simon, M.D. pursuant to which the Company agreed to pay Dr. Simon certain
royalty payments based on sales of products using the technology invented by Dr.
Simon relating to the Company's Simon Nitinol Filter. Dr. Simon assigned a
percentage of his royalty payments to the Beth Israel Hospital Association. In
February 1998, the Company and Dr. Simon entered into a two-year consulting
agreement pursuant to which Dr. Simon agreed to perform certain consulting and
advisory services for the Company, such services not to exceed eight days per
month. The Company agreed to pay Dr. Simon $8,333 per month for such services as
well as certain royalty payments and license fees based on sales of products
which are covered by an issued patent and which are developed by Dr. Simon,
solely or jointly with others, during the term of the consulting agreement. The
term of the consulting agreement will be automatically extended for successive
one-year periods unless either party gives 60 days' prior written notice. If the
Company terminates the agreement, other than for material breach, the Company
will be obligated to continue to pay Dr. Simon's monthly consulting fee for
twelve months and will be obligated to continue to make royalty and license fee
payments. In the event of Dr. Simon's death, the royalty payments and license
fees shall continue to be payable to the executors or personal representatives
of his estate. In addition, in connection with the consulting arrangement, Dr.
Simon received non-qualified stock options to purchase 50,000 shares of Common
Stock of the Company at an exercise price of $10.50 per share. The options vest
upon the achievement of certain milestones as described in the option
agreements, are exercisable for a period of ten years after the date of grant
and become immediately exercisable in the event of a change of control of the
Company. Certain of the shares of Common Stock issuable upon exercise of the
options are subject to "piggy-back" registration rights. The Company paid Dr.
Simon $100,000 in 1999 for such services.

  From June 1999 through November 1999, Fletcher Spaght provided certain
consulting services to the Company, for which services the Company paid
approximately $109,000 to Fletcher Spaght.  R. John Fletcher, a member of the
Board of Directors of the Company is currently the Chief Executive Officer of
Fletcher Spaght.  Fletcher Spaght is a beneficial owner of more than 5% of the
outstanding shares of Common Stock.

                                       11
<PAGE>

                                   SIGNATURES

     Pursuant to the requirements of Section 13 or 15(d) of the Securities
Exchange Act of 1934, the Registrant has duly caused this report to be signed on
its behalf by the undersigned, thereunto duly authorized.


                                  NMT MEDICAL, INC.


                                  By:  /s/ William J. Knight
                                       _________________________________________
                                       William J. Knight
                                       Vice President-Finance and Administration
                                       and Chief Financial Officer

Dated:  May 1, 2000

                                       12