-----BEGIN PRIVACY-ENHANCED MESSAGE-----
Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
Originator-Key-Asymmetric:
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 TWSM7vrzLADbmYQaionwg5sDW3P6oaM5D3tdezXMm7z1T+B+twIDAQAB
MIC-Info: RSA-MD5,RSA,
 Q+zTP3LY8ZiBGzN0CjgnD7ZGwYNBBHqim00C8RHWet+FFg8n7km5ePOqVtp9aqzK
 t+JhldYZf3NgpFS7nbwVEw==

<SEC-DOCUMENT>0001179110-05-022420.txt : 20051206
<SEC-HEADER>0001179110-05-022420.hdr.sgml : 20051206
<ACCEPTANCE-DATETIME>20051206161410
ACCESSION NUMBER:		0001179110-05-022420
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20051205
FILED AS OF DATE:		20051206
DATE AS OF CHANGE:		20051206

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			REILLY PHILIP R
		CENTRAL INDEX KEY:			0001237194

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-23413
		FILM NUMBER:		051247279

	MAIL ADDRESS:	
		STREET 1:		C/O INTERLEUKIN GENETICS INC
		STREET 2:		135 BEAVER STREET
		CITY:			WALTHAM
		STATE:			MA
		ZIP:			02452

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			INTERLEUKIN GENETICS INC
		CENTRAL INDEX KEY:			0001037649
		STANDARD INDUSTRIAL CLASSIFICATION:	IN VITRO & IN VIVO DIAGNOSTIC SUBSTANCES [2835]
		IRS NUMBER:				943123681
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		135 BEAVER ST
		CITY:			WATHAM
		STATE:			MA
		ZIP:			02452
		BUSINESS PHONE:		1-781-398-0700

	MAIL ADDRESS:	
		STREET 1:		135 BEAVER ST
		CITY:			WATHAM
		STATE:			MA
		ZIP:			02452

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	MEDICAL SCIENCE SYSTEMS INC
		DATE OF NAME CHANGE:	19971003
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>edgar.xml
<DESCRIPTION>FORM 4 -
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0202</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2005-12-05</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001037649</issuerCik>
        <issuerName>INTERLEUKIN GENETICS INC</issuerName>
        <issuerTradingSymbol>ILGN</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001237194</rptOwnerCik>
            <rptOwnerName>REILLY PHILIP R</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>135 BEAVER STREET</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>WALTHAM</rptOwnerCity>
            <rptOwnerState>MA</rptOwnerState>
            <rptOwnerZipCode>02452</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Chief Executive Officer</officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2005-12-05</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>M</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>20000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0.50</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>30000</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>73275</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See Footnote</value>
                    <footnoteId id="F1"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">The reporting person disclaims beneficial ownership of these securities and the filing of this report is not an admission that the reporting person is the beneficial owner of these securities for purposes of Section 16 or any other purposes.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/Philip R. Reilly</signatureName>
        <signatureDate>2005-12-06</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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