SIGA Announces $2.3 Million in New Contracts with the U.S. Air Force.

NEW YORK -- SIGA Technologies, Inc. (NASDAQ: SIGA) today announced receipt of two contracts from the U.S. Air Force for a total of $2.3 million. SIGA received a one-year, $1.4 million contract with the Air Force Medical Service for the development of counter-measures against important potential biowarfare pathogens, the Dengue viruses, and other water-related viral agents. SIGA also received a one-year, $900,000 contract to aid the USAF Special Operations Command (USAFSOC) in its development of specific anti-viral agents, focusing on orthopoxvirus targets distinct from the target that is the focus of SIGA-246, the Company's lead smallpox drug.

"We appreciate the opportunity to continue the development of these critical biological defense capabilities with our colleagues from the Air Force," said Dr. Dennis E. Hruby, Chief Scientific Officer of SIGA.

Dengue fever and Dengue hemorrhagic fever are acute febrile mosquito-borne diseases caused by one of four closely related virus serotypes of the genus Flaviviridae. The two diseases affect tens of millions of people worldwide every year and present a biodefense threat in the U.S. Currently, there is no approved drug or vaccine against Dengue, leaving troops vulnerable overseas and in areas affected by flooding.

SIGA recently announced a breakthrough in its SIGA-246 program with the successful completion of a preliminary primate trial in which the drug completely prevented smallpox disease.

About SIGA Technologies, Inc.

SIGA Technologies is applying viral and bacterial genomics and sophisticated computational modeling in the design and development of novel products for the prevention and treatment of serious infectious diseases, with an emphasis on products for biological warfare defense. SIGA believes that it is a leader in the development of pharmaceutical agents and vaccines to fight potential biowarfare pathogens. In addition to smallpox, SIGA has antiviral programs targeting other Category A pathogens, including arenaviruses (Lassa fever, Junin, Machupo, Guanarito, Sabia, and lymphocytic choriomeningitis), dengue virus, and the filoviruses (Ebola and Marburg).

For more information about SIGA, please visit SIGA's Web site at www.siga.com.

Forward-looking Statements

This Press Release contains or implies certain "forward-looking statements" within the meaning of the Private Securities Litigation Reform Act of 1995, as amended, including statements regarding the efficacy of potential products, the timelines for bringing such products to market and the availability of funding sources for continued development of such products. Forward-looking statements are based on management's estimates, assumptions and projections, and are subject to uncertainties, many of which are beyond the control of SIGA. Actual results may differ materially from those anticipated in any forward-looking statement. Factors that may cause such differences include the risks that (a) potential products that appear promising to SIGA or its collaborators cannot be shown to be efficacious or safe in subsequent pre-clinical or clinical trials, (b) SIGA or its collaborators will not obtain appropriate or necessary governmental approvals to market these or other potential products, (c) SIGA may not be able to obtain anticipated funding for its development projects or other needed funding, (d) SIGA may not be able to secure funding from anticipated government contracts and grants, (e) SIGA may not be able to secure or enforce adequate legal protection, including patent protection for its products and (f) regulatory approval for SIGA's products may require further or additional testing that will delay or prevent approval. More detailed information about SIGA and risk factors that may affect the realization of forward-looking statements, including the forward-looking statements in this Press Release, is set forth in SIGA's filings with the Securities and Exchange Commission, including SIGA's Annual Report on Form 10-K for the fiscal year ended December 31, 2005, and in other documents that SIGA has filed with the Commission. SIGA urges investors and security holders to read those documents free of charge at the Commission's Web site at http://www.sec.gov. Interested parties may also obtain those documents free of charge from SIGA. Forward-looking statements speak only as to the date they are made, and, except for any obligation under the U.S. federal securities laws, SIGA undertakes no obligation to publicly update any forward-looking statement as a result of new information, future events or otherwise.