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As filed with the Securities and Exchange Commission on January 22, 1997.
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                     SECURITIES AND EXCHANGE COMMISSION
                            WASHINGTON, D.C.  20549

                                 FORM 10-K/A
                               AMENDMENT NO. 1
                                --------------
 /X/          ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE
                       SECURITIES EXCHANGE ACT OF 1934

                 FOR THE FISCAL YEAR ENDED OCTOBER 31, 1996

                                     OR

 / /  TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES
                            EXCHANGE ACT OF 1934

            For the Transition period from         to
                                           --------  ------------

                        COMMISSION FILE NUMBER 1-9579

                                 ECOGEN INC.
           (EXACT NAME OF REGISTRANT AS SPECIFIED IN ITS CHARTER)

        DELAWARE                                        22-2487948
                                                        ----------
                                                      
(State or other Jurisdiction of             (I.R.S. Employer Identification No.)
incorporation or organization)                        
                                                      
 2005 CABOT BOULEVARD WEST                                19047
 LANGHORNE, PENNSYLVANIA                                (Zip Code)
 (ADDRESS OF PRINCIPAL EXECUTIVE OFFICES)             

 Registrant's telephone number, including area code:    (215) 757-1590
                                                        --------------

          SECURITIES REGISTERED PURSUANT TO SECTION 12(b) OF THE ACT:

                                    NONE

         SECURITIES REGISTERED PURSUANT TO SECTION 12(g) OF THE ACT:

                        COMMON STOCK, $.01 PAR VALUE


 WARRANTS TO PURCHASE COMMON STOCK AT AN EXERCISE PRICE OF $43.75 PER SHARE.

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.
                    /X/   YES                    / /     NO

 THE APPROXIMATE AGGREGATE MARKET VALUE OF VOTING STOCK HELD BY NON-AFFILIATES
          OF THE REGISTRANT IS $20,493,052 AS OF JANUARY 3, 1997.  (A)

                                   7,801,523

      (NUMBER OF SHARES OF COMMON STOCK OUTSTANDING AS OF JANUARY 3, 1997)

                                     5,834

          (NUMBER OF SHARES OF CONVERTIBLE PREFERRED STOCK OUTSTANDING
                             AS OF JANUARY 3, 1997)

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.  / /
   2
              AMENDMENT NO. 1 TO THE ANNUAL REPORT ON FORM 10-K
                    FOR FISCAL YEAR ENDED OCTOBER 31, 1996

        The undersigned registrant hereby amends its Annual Report on Form 10-K
for the fiscal year ended October 31, 1996 for the sole purpose of adding the
registrant's signature which was inadvertently omitted in the previously filed
Form 10-K.



                                  SIGNATURE

        In accordance with Section 13 or 15(d) of the Exchange Act, the
registrant caused this Report to be signed on its behalf by the undersigned,
thereunto duly authorized.

                                        ECOGEN INC.


                                        By: /s/ Mary E. Paetzold
                                           ---------------------
                                           Mary E. Paetzold
                                           Vice President, Chief Financial 
                                           Officer and Treasurer


Date:   January 20, 1997







                                  SIGNATURE

        Pursuant to the requirements of the Securities Exchange Act of 1934,
the registrant has duly caused this Amendment No. 1 to be signed on its behalf
by the undersigned, thereunto duly authorized.


                                        ECOGEN INC.


                                        By: /s/ Richard A. Deak
                                           --------------------
                                           Richard A. Deak
                                           Vice President, General Counsel and
                                           Secretary


Date:   January 22, 1997