<DOCUMENT>
<TYPE>EX-32.1
<SEQUENCE>5
<FILENAME>d63845_ex32-1.txt
<DESCRIPTION>SECTION 1350 CERTIFICATIONS
<TEXT>

                                                                    Exhibit 32.1

                            CERTIFICATION PURSUANT TO
                             18 U.S.C. SECTION 1350,
                             AS ADOPTED PURSUANT TO
                  SECTION 906 OF THE SARBANES-OXLEY ACT OF 2002

      In connection with the Quarterly  Report of SIGA  Technologies,  Inc. (the
"Company") on Form 10-Q for the three months ending March 31, 2005 as filed with
the Securities  and Exchange  Commission on the date hereof (the  "Report"),  I,
Bernard L.  Kasten,  M.D.,  Chief  Executive  Officer of the  Company,  certify,
pursuant  to  18  U.S.C.   ss.1350,   as  adopted  pursuant  to  ss.906  of  the
Sarbanes-Oxley Act of 2002, that, to the best of my knowledge:

      (1)   The Report fully complies with the  requirements of section 13(a) or
            15(d) of the Securities Exchange Act of 1934; and

      (2)   The  information  contained in the Report  fairly  presents,  in all
            material respects, the financial condition and results of operations
            of the Company.

May 13, 2005

                                        By: /s/ Bernard L. Kasten, M.D.
                                           ---------------------------------
                                           Bernard L. Kasten, M.D.
                                           Chief Executive Officer
</TEXT>
</DOCUMENT>
