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                       SECURITIES AND EXCHANGE COMMISSION
                              Washington, DC 20549

                                    FORM 10-K/A

   ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(D) OF THE SECURITIES ACT OF 1934

                      For Fiscal Year Ended March 31, 1999
                                            --------------

                         Commission File Number      0-23252
                                                -----------------

                            IGEN INTERNATIONAL, INC.
                            ------------------------
             (Exact name of registrant as specified in its charter)

            DELAWARE                                               94-2852543
-------------------------------------------------------------------------------
(State or other jurisdiction of              (IRS Employer Identification No.)
 incorporation or organization)

16020 INDUSTRIAL DRIVE, GAITHERSBURG, MD                          20877
--------------------------------------------------------------------------------
(Address of principal executive offices)                        (Zip Code)

                                  301/984-8000
     ----------------------------------------------------------------------
              (Registrant's telephone number, including area code)

Securities registered pursuant to Section 12(b) of the Act: NONE

Securities registered pursuant to Section 12(g)
 of the Act:                                    COMMON STOCK $0.001 PAR VALUE
                                                -----------------------------
                                                       (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 the voting and non-voting equity held by
non-affiliates of the Registrant as of June 11, 1999, computed by reference to
the closing sale price of such stock quoted on the Nasdaq National Market, was
approximately $271,638,100. For the purposes of this calculation, shares owned
by officers, directors and 5% shareholders known to the Registrant have been
deemed to be owned by affiliates.

The number of shares outstanding of the Registrant's Common Stock as of June 11,
1999 was 15,372,600.

                       DOCUMENTS INCORPORATED BY REFERENCE

The following documents (or parts thereof) are incorporated by reference into
the following parts of this Form 10-K. Certain information required in Part III
of this Annual Report on Form 10-K is incorporated from the Company's definitive
Proxy Statement relating to its Annual Meeting of Shareholders to be held on
September 15, 1999.

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                                   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.

                                  IGEN International, Inc.


June 30, 1999                     By: /s/ George V. Migausky
                                     ---------------------------
                                     Vice President and
                                     Chief Financial Officer


Pursuant to the requirements of the Securities Exchange Act of 1934, this report
has been signed below by the following persons on behalf of the registrant and
in the capacities and on the dates indicated.

Signature                            Title                            Date

/s/      *                    Chief Executive Officer            June 30, 1999
-------------------------     (Principal Executive Officer);
Samuel J. Wohlstadter         Director

/s/ George V. Migausky        Vice President                     June 30, 1999
-------------------------     and Chief Financial Officer
George V. Migausky            (Principal Financial and
                              Accounting Officer)

/s/      *                    President, Chief Operating         June 30, 1999
-------------------------     Officer; Director
Richard J. Massey

/s/      *                    Director                           June 30, 1999
------------------------
Edward Lurier

/s/      *                    Director                           June 30, 1999
------------------------
William O'Neill

/s/      *                    Director                           June 30, 1999
------------------------
Robert Salsmans



* By: /s/ George V. Migausky
      ----------------------
      George V. Migausky
      Attorney-in-Fact


                                       55

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                                INDEX TO EXHIBITS

<TABLE>
<CAPTION>

EXHIBIT
NUMBER                                  DESCRIPTION OF DOCUMENT
------                                  -----------------------
<S>               <C>
2.1(4)            Agreement and Plan of Merger effective November 19, 1996 (by virtue of a
                  reincorporation), by and between IGEN, Inc., a California corporation (the "Company"),
                  and IGEN International, Inc. a Delaware corporation (the "Registrant").
3.1(4)            The Registrant's Certificate of Incorporation, as filed with the Secretary of State of
                  the State of Delaware on August 30, 1996.
3.2(4)            The Registrant's  Certificate of Designation of Series A Junior Participating  Preferred
                  Stock, as filed with the Secretary of State of the State of Delaware on November  18,
                  1996.
3.3(8)            The Registrant's Certificate of Designation of Series B
                  Convertible Preferred Stock, as field with the Secretary of
                  State of the State of Delaware on December 18, 1997.
3.4(4)            The Registrant's Bylaws, as currently in effect.
4.1(7)            Form of Specimen Right Certificate.
4.2(7)            Rights Agreement, dated November 6, 1996, between the Registrant and The First
                  National Bank of Boston.
4.3(9)            Note Purchase Agreement between the Registrant and the purchasers named therein dated
                  as of March 22, 1999.
10.1(1)           Registration Agreement between the Registrant and the parties
                  named therein dated March 17, 1988, as amended through
                  March 30, 1993.
10.2(3)           Form of Waiver and Amendment of Registration Agreement executed
                  in December 1993, amending in certain respects the Registration
                  Agreement dated as of March 17, 1988.
10.3(3)           Agreement between the Registrant and The Perkin-Elmer Corporation
                  dated March 30, 1990, with Addendum to Agreement dated February 21,
                  1991 (with certain confidential information deleted).
10.4(3)           Agreement between the Registrant and Eisai Co., Ltd. dated May 25,
                  1990 (with certain confidential information deleted).
10.4.1(1)         Supplemental Agreement between Eisai Co., Ltd. and the Registrant
10.5(3)           License and Development Technology Agreement between the Registrant
                  and Boehringer Mannheim GmbH dated September 23, 1992 (with
                  certain confidential information deleted).
10.5.1(2)         Advanced Royalty Agreement between the Registrant and
                  Boehringer Mannheim GmbH dated January 9, 1997.
10.6(3)           License Agreement between the Registrant and Hyperion Catalysis
                  International ("Hyperion") dated October 10, 1993 as amended March 15,
                  1990.
10.7(3)           Common Stock Purchase Agreement between the Registrant and Organon
                  Teknika B.V. ("Organon") dated May 19, 1993.

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                                       56

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<TABLE>
<CAPTION>

EXHIBIT
NUMBER                                  DESCRIPTION OF DOCUMENT
------                                  -----------------------
<S>               <C>
10.8(3)           License and Technology Development agreement between the Registrant
                  and Organon dated May 19, 1993 (with certain confidential information
                  deleted).
10.9(3)           Agreement and Plan of Reorganization and Agreement and Plan of Merger
                  between the Registrant and Molecular Displays, Inc. dated March 9, 1993.
10.103            Term Sheet for Consolidation of Research Projects between the Registrant and
                  Proteinix Corporation dated December 14, 1993 (with certain confidential
                  information deleted).
10.11(3)          Term Sheet for consolidation of Cancer Research Projects between the
                  Registrant and Pro-Neuron, Inc. dated December 14, 1993 (with certain
                  confidential information deleted).
10.12(3)          Join Venture Agreement between the Registrant and Hyperion dated
                  May 28, 1993.
10.13(3)          Product Development and Marketing Agreement between the
                  Registrant, Hyperion and HyperGen dated May 29, 1993.
10.14(3)          Form of Indemnity Agreement entered into between the Registrant and its
                  directors and officers.
10.15(3)          Registrant's 1985 Stock Option Plan, as amended, and related Form of
                  Incentive Stock Option Grant and Form of Nonqualified Stock Option Grant.
10.16(5)          Registrant's 1994 Stock Option Plan, and related Form of Incentive Stock
                  Option Grant.
10.17(5)          Registrant's 1994 Non-Employee Directors Stock Option Plan, and related
                  Form of Incentive  Stock Option Grant.
10.18(5)          Lease Agreement between the Registrant and W-M 16020 Limited
                  Partnership dated October 5, 1994.
10.19(5)          Agreement for Purchase and Sale of Joint Venture Interest
                  between the Registrant and Hyperion, dated December 28, 1994
10.20(6)          Joint Venture Agreement, dated as of November 30, 1995, between Meso Scale
                  Diagnostics, LLC ("MSD"), Meso Scale Technologies, LLC ("MST")
                  and the Company.
10.21(6)          Limited Liability Company Agreement, dated as of November 30, 1995, between MSD, MST
                  and the Company.
10.22(6)          IGEN/MSD License Agreement, dated as of November 30, 1995, between MSD and the Company.
10.23(6)          Indemnification  Agreement, dated as of November 30, 1995, between the Company and
                  Jacob Wohlstadter.
10.24(8)          Purchase Agreement for the Series B Convertible Preferred Stock between the Registrant
                  and the purchasers named therein dated as of December 16, 1997.
10.25(8)          Registration Rights Agreement between the Registrant and the purchasers named therein
                  dated as of December 16, 1997.
11.1              Calculation of net loss per share. Filed herewith.

23.1(9)           Consent of Deloitte & Touche LLP.

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                                       57

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<TABLE>
<CAPTION>

EXHIBIT
NUMBER                                  DESCRIPTION OF DOCUMENT
------                                  -----------------------
<S>               <C>
27.1              Financial Data Schedule.

</TABLE>

------------
(1)   Previously filed as an exhibit to the Registrant's Form 10-Q for the
      quarter ended September 30, 1997.

(2)   Previously filed as an exhibit to the Registrant's Annual Report on Form
      10-K, as amended, for the fiscal year ended March 31, 1997.

(3)   Previously filed as an exhibit to the Registration Statement on Form S-1,
      as amended (Registration No. 33-72992) and incorporated by reference
      herein.

(4)   Previously filed as an exhibit to the Registrant's Form 10-Q for the
      quarter ended December 31, 1996.

(5)   Previously filed as an exhibit to the Registrant's Annual Report on Form
      10-K for the fiscal year ended March 31, 1995.

(6)   Previously filed as an exhibit to the Registrant's Form 10-Q for the
      quarter ended December 31, 1995.

(7)   Incorporated by reference to Exhibit 1.1 of the Registrant's Form 8-A
      filed December 10, 1996.

(8)   Previously filed as an exhibit to the Registrant's Registration Statement
      on Form S-3, as amended (Registration No. 333-45355).

(9)   Previously filed as an exhibit to the Registrant's Annual Report on
      Form 10-K, for the fiscal year ended March 31, 1999.

                                       58