Exhibit 23.1 CONSENT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM We hereby consent to the incorporation by reference in this Registration Statement on Form S-3 of our report dated February 17, 2004 relating to the financial statements, which appears in SIGA Technologies, Inc.'s Annual Report on Form 10-KSB for the year ended December 31, 2003. We also consent to the reference to us under the heading "Experts" in such Registration Statement. /s/ PricewaterhouseCoopers LLP - ------------------------------ PricewaterhouseCoopers LLP New York, New York November 23, 2004