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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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 O3ZkPo1pY5b/EmGWEeQlhA==

<SEC-DOCUMENT>0001104659-03-027075.txt : 20031119
<SEC-HEADER>0001104659-03-027075.hdr.sgml : 20031119
<ACCEPTANCE-DATETIME>20031119165215
ACCESSION NUMBER:		0001104659-03-027075
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20031117
FILED AS OF DATE:		20031119

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			THIBAULT LANCE E
		CENTRAL INDEX KEY:			0001158485

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-30469
		FILM NUMBER:		031013383

	BUSINESS ADDRESS:	
		STREET 1:		124 MT. AUBURN STREET
		STREET 2:		SUITE 200 NORTH
		CITY:			CAMBRIDGE
		STATE:			MA
		ZIP:			02138
		BUSINESS PHONE:		9783737329

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:		LYNGHALS 1
		STREET 2:		REYJKAVIK
		CITY:			ICELAND
		STATE:			K6
		ZIP:			00000
		BUSINESS PHONE:		0113545701900

	MAIL ADDRESS:	
		STREET 1:		LYNGHALSI 1
		STREET 2:		REYKJAVIK
		CITY:			ICELAND
		STATE:			K6
		ZIP:			00000
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>a4.xml
<DESCRIPTION>4
<TEXT>
<XML>
<?xml version="1.0" encoding="utf-8"?>
<ownershipDocument>
    <schemaVersion>X0201</schemaVersion>

    <documentType>4</documentType>
  <periodOfReport>2003-11-17</periodOfReport>
  <notSubjectToSection16>0</notSubjectToSection16>
    <issuer>
        <issuerCik>0001022974</issuerCik>
        <issuerName>DECODE GENETICS INC</issuerName>
        <issuerTradingSymbol>DCGN</issuerTradingSymbol>
  </issuer>
  <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001158485</rptOwnerCik>
            <rptOwnerName>THIBAULT LANCE E</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1></rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity></rptOwnerCity>
            <rptOwnerState></rptOwnerState>
            <rptOwnerZipCode></rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
            <reportingOwnerRelationship>
      <isDirector>0</isDirector>
      <isOfficer>1</isOfficer>
      <isTenPercentOwner>0</isTenPercentOwner>
      <isOther>0</isOther>
      <officerTitle>CFO &amp; Treasurer</officerTitle>
    </reportingOwnerRelationship>
  </reportingOwner>
  <derivativeTable>
    <derivativeTransaction>
      <securityTitle>
        <value>Option</value>
      </securityTitle>
      <conversionOrExercisePrice>
        <value>8.960</value>
      </conversionOrExercisePrice>
      <transactionDate>
        <value>2003-11-17</value>
      </transactionDate>
      <transactionCoding>
        <transactionFormType>4</transactionFormType>
        <transactionCode>A</transactionCode>
        <equitySwapInvolved>0</equitySwapInvolved>
      </transactionCoding>
      <transactionTimeliness>
        <value></value>
      </transactionTimeliness>
      <transactionAmounts>
        <transactionShares>
          <value>50000</value>
        </transactionShares>
        <transactionPricePerShare>
          <value>0</value>
        </transactionPricePerShare>
        <transactionAcquiredDisposedCode>
          <value>A</value>
        </transactionAcquiredDisposedCode>
      </transactionAmounts>
      <exerciseDate>
        <footnoteId id="F1"/>
      </exerciseDate>
      <expirationDate>
        <value>2013-11-17</value>
      </expirationDate>
      <underlyingSecurity>
        <underlyingSecurityTitle>
          <value>Common Stock</value>
        </underlyingSecurityTitle>
        <underlyingSecurityShares>
          <value>50000</value>
        </underlyingSecurityShares>
      </underlyingSecurity>
      <postTransactionAmounts>
        <sharesOwnedFollowingTransaction>
          <value>50000</value>
        </sharesOwnedFollowingTransaction>
      </postTransactionAmounts>
      <ownershipNature>
        <directOrIndirectOwnership>
          <value>D</value>
        </directOrIndirectOwnership>
      </ownershipNature>
    </derivativeTransaction>
  </derivativeTable>
  <footnotes>
    <footnote id="F1">The options vest as follows: 1/48th on the last day of each calendar month commencing November 30, 2003.</footnote>
  </footnotes>
  <ownerSignature>
    <signatureName>/s/ Lance Thibault</signatureName>
    <signatureDate>2003-11-19</signatureDate>
  </ownerSignature>
</ownershipDocument>

</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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