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                                  UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549

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                                   FORM 10-Q/A
                                (Amendment No. 1)

(Mark One)

|X|   Quarterly Report Pursuant to Section 13 or 15(d) of the Securities
      Exchange Act of 1934

      For the Quarter Ended September 30, 2006

                                       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 No. 0-23047

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                             SIGA Technologies, Inc.
             (Exact name of registrant as specified in its charter)

   A Delaware Corporation                            IRS Employer No. 13-3864870

               420 Lexington Avenue, Suite 408, New York, NY 10170
                         Telephone Number (212) 672-9100

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 whether the registrant is a large  accelerated  filer, an
accelerated  filer, or a  non-accelerated  filer. See definition of "accelerated
filer and large  accelerated  filer" in Rule 12b-2 of the Exchange  Act.  (Check
one):

Large Accelerated Filer |_| Accelerated Filer |_| Non-Accelerated Filer |X|.

Indicate by check mark whether the  registrant is a shell company (as defined in
rule 12b-2 of the Exchange Act). Yes |_| No |X|.

As of October 31, 2006 the  registrant  had  31,765,621  shares of common  stock
outstanding.

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                                EXPLANATORY NOTE

      This  Amendment  No.  1 on  Form  10-Q/A  (this  "Amendment")  amends  the
Quarterly  Report on Form 10-Q for the quarterly period ended September 30, 2006
filed on November 1, 2006 (the "Original Filing").  We have filed this Amendment
solely to include the information  required by Part II, Item 6 - Exhibits.  This
information was inadvertently  omitted from the Original Filing. In addition, in
connection  with the filing of this  Amendment  and pursuant to the rules of the
Securities and Exchange Commission, we are including with this Amendment certain
currently dated certifications.

      Except as described above, no other changes have been made to the Original
Filing.  This  Amendment  has not  resulted  in any  changes  to our  previously
reported financial results.  This Amendment continues to speak as of the date of
the Original Filing,  and we have not updated the disclosures  contained in this
Amendment  to reflect  any events  that  occurred  at a date  subsequent  to the
Original Filing.

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                                     Part II
                                Other information

Item 6. Exhibits

*   10.1   Contract, dated September 29, 2006, between SIGA Technologies, Inc.
           and the National Institute of Allergy and Infectious Diseases of the
           National Institutes for Health.

*     31   Certification of Chief Financial Officer and Acting Chief Executive
           Officer Pursuant to Section 302 of the Sarbanes-Oxley Act of 2002.

*     32   Certification of Chief Financial Officer and Acting Chief Executive
           Officer Pursuant to Section 906 of the Sarbanes-Oxley Act of 2002.

* Filed herein

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                                   SIGNATURES

Pursuant to the requirements 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.

                                              SIGA Technologies, Inc.
                                              (Registrant)

      Date: November 13, 2006                  By: /s/ Thomas N. Konatich
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                                              Thomas N. Konatich

                                              Chief Financial Officer and
                                              Acting Chief Executive Officer

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