-----BEGIN PRIVACY-ENHANCED MESSAGE-----
Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
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MIC-Info: RSA-MD5,RSA,
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 IqEgUgybZVHE8lp+JFdcPw==

<SEC-DOCUMENT>0001140361-09-007326.txt : 20090317
<SEC-HEADER>0001140361-09-007326.hdr.sgml : 20090317
<ACCEPTANCE-DATETIME>20090317171105
ACCESSION NUMBER:		0001140361-09-007326
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20090316
FILED AS OF DATE:		20090317
DATE AS OF CHANGE:		20090317

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			SLOVIN BRUCE
		CENTRAL INDEX KEY:			0001248295

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-23047
		FILM NUMBER:		09688762

	MAIL ADDRESS:	
		STREET 1:		35 E 62ND ST
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10021

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			SIGA TECHNOLOGIES INC
		CENTRAL INDEX KEY:			0001010086
		STANDARD INDUSTRIAL CLASSIFICATION:	PHARMACEUTICAL PREPARATIONS [2834]
		IRS NUMBER:				133864870
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		420 LEXINGTON AVE
		STREET 2:		SUITE 408
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10170
		BUSINESS PHONE:		2126729100

	MAIL ADDRESS:	
		STREET 1:		420 LEXINGTON AVE
		STREET 2:		SUITE 408
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10170

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	SIGA PHARMACEUTICALS INC
		DATE OF NAME CHANGE:	19961108
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>doc1.xml
<DESCRIPTION>FORM 4
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0303</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2009-03-16</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001010086</issuerCik>
        <issuerName>SIGA TECHNOLOGIES INC</issuerName>
        <issuerTradingSymbol>SIGA</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001248295</rptOwnerCik>
            <rptOwnerName>SLOVIN BRUCE</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O SIGA TECHNOLOGIES, INC.</rptOwnerStreet1>
            <rptOwnerStreet2>420 LEXINGTON AVENUE, SUITE 408</rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10170</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock, par value $.0001 per share</value>
            </securityTitle>
            <transactionDate>
                <value>2009-03-16</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>15000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>5.07</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>20000</value>
                    <footnoteId id="F1"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By Daughter</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock, par value $.0001 per share</value>
            </securityTitle>
            <transactionDate>
                <value>2009-03-16</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>15000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>5.08</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>20000</value>
                    <footnoteId id="F1"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By Spouse</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">Does not include 15,000 shares owned by Mr. Slovin's wife and 15,000 shares owned by Mr. Slovin's daughter as reported on the Form 4 filed with the Securities and Exchange Commission on December 8, 2008, or the 15,000 shares owned by Mr. Slovin's wife and 15,000 shares owned by Mr. Slovin's daughter as reported on this Form 4, which Mr. Slovin may be deemed to beneficially own and as to which Mr. Slovin disclaims beneficial ownership.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Bruce Slovin</signatureName>
        <signatureDate>2009-03-17</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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