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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>0001031836-04-000001.txt : 20040205
<SEC-HEADER>0001031836-04-000001.hdr.sgml : 20040205
<ACCEPTANCE-DATETIME>20040205175252
ACCESSION NUMBER:		0001031836-04-000001
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20040203
FILED AS OF DATE:		20040205

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			ILLUMINA INC
		CENTRAL INDEX KEY:			0001110803
		STANDARD INDUSTRIAL CLASSIFICATION:	LABORATORY ANALYTICAL INSTRUMENTS [3826]
		IRS NUMBER:				330804655
		STATE OF INCORPORATION:			CA
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		9885 TOWNE CENTRE DRIVE
		STREET 2:		.
		CITY:			SAN DIEGO
		STATE:			CA
		ZIP:			92121
		BUSINESS PHONE:		8582024500

	MAIL ADDRESS:	
		STREET 1:		9885 TOWN CENTRE DRIVE
		STREET 2:		.
		CITY:			SAN DIEGO
		STATE:			CA
		ZIP:			92121

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			ARCH VENTURE FUND III L P
		CENTRAL INDEX KEY:			0001031836
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-30361
		FILM NUMBER:		04571108

	BUSINESS ADDRESS:	
		STREET 1:		8725 W HIGGINS ROAD
		STREET 2:		SUITE 290
		CITY:			CHICAGO
		STATE:			IL
		ZIP:			60631
		BUSINESS PHONE:		7733806600

	MAIL ADDRESS:	
		STREET 1:		8725 W HIGGINS ROAD
		STREET 2:		SUITE 290
		CITY:			CHICAGO
		STATE:			IL
		ZIP:			60631
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>primary_doc.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0201</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2004-02-03</periodOfReport>

    <notSubjectToSection16>1</notSubjectToSection16>

    <issuer>
        <issuerCik>0001110803</issuerCik>
        <issuerName>ILLUMINA INC</issuerName>
        <issuerTradingSymbol>ILMN</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001031836</rptOwnerCik>
            <rptOwnerName>ARCH VENTURE FUND III L P</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>8725 W HIGGINS ROAD</rptOwnerStreet1>
            <rptOwnerStreet2>SUITE 290</rptOwnerStreet2>
            <rptOwnerCity>CHICAGO</rptOwnerCity>
            <rptOwnerState>IL</rptOwnerState>
            <rptOwnerZipCode>60631</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>1</isOther>
            <otherText>Former 10% Holder</otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2004-02-03</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>J</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F1"/>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>400000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>2915298</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">Distribution of Common Stock held by a limited partnership to its partners for no consideration.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>ARCH Venture Fund III, L.P., By: ARCH Venture Partners, LLC, Its General Partner, By: Keith Crandell, Managing Director</signatureName>
        <signatureDate>2004-02-05</signatureDate>
    </ownerSignature>
</ownershipDocument>

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