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Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
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MIC-Info: RSA-MD5,RSA,
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<SEC-DOCUMENT>0001104659-08-037246.txt : 20080602
<SEC-HEADER>0001104659-08-037246.hdr.sgml : 20080602
<ACCEPTANCE-DATETIME>20080602152212
ACCESSION NUMBER:		0001104659-08-037246
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20080529
FILED AS OF DATE:		20080602
DATE AS OF CHANGE:		20080602

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			DECODE GENETICS INC
		CENTRAL INDEX KEY:			0001022974
		STANDARD INDUSTRIAL CLASSIFICATION:	SERVICES-COMMERCIAL PHYSICAL & BIOLOGICAL RESEARCH [8731]
		IRS NUMBER:				043326704
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		8 STURLUGATA
		STREET 2:		IS 101
		CITY:			REYJKAVIK
		STATE:			K6
		ZIP:			00000
		BUSINESS PHONE:		011 354 570 1900

	MAIL ADDRESS:	
		STREET 1:		8 STURLUGATA
		STREET 2:		IS 101
		CITY:			REYKJAVIK
		STATE:			K6
		ZIP:			00000

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			ARMSTRONG J NEAL
		CENTRAL INDEX KEY:			0001222938

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-30469
		FILM NUMBER:		08873709

	BUSINESS ADDRESS:	
		BUSINESS PHONE:		6175597000

	MAIL ADDRESS:	
		STREET 1:		C/O ASPECT MEDICAL SYSTEMS INC
		STREET 2:		141 NEEDHAM ST
		CITY:			NEWTON
		STATE:			MA
		ZIP:			02464-1505
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>a4.xml
<DESCRIPTION>4
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0202</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2008-05-29</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001022974</issuerCik>
        <issuerName>DECODE GENETICS INC</issuerName>
        <issuerTradingSymbol>DCGN</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001222938</rptOwnerCik>
            <rptOwnerName>ARMSTRONG J NEAL</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O ASPECT MEDICAL SYSTEMS INC</rptOwnerStreet1>
            <rptOwnerStreet2>141 NEEDHAM ST</rptOwnerStreet2>
            <rptOwnerCity>NEWTON</rptOwnerCity>
            <rptOwnerState>MA</rptOwnerState>
            <rptOwnerZipCode>02464-1505</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2008-05-29</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>20339</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <footnoteId id="F2"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>33931</value>
                    <footnoteId id="F3"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">One quarter of the shares of stock acquired are vested; provided that Mr. Armstrong is then serving as Chairman of the issuer's Audit Committee, beginning on September 30, 2008 an additional one quarter of the shares of stock acquired shall vest on the last day of each calendar quarter.</footnote>
        <footnote id="F2">Issued in consideration of service as the Chairman of the issuer's Audit Committee.</footnote>
        <footnote id="F3">Includes shares which have not yet vested (See FN 1).</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ J. Neal Armstrong</signatureName>
        <signatureDate>2008-05-29</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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