-----BEGIN PRIVACY-ENHANCED MESSAGE-----
Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
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MIC-Info: RSA-MD5,RSA,
 Sr9HBHmsjYjd+tkEa2VdLr/fJm41liuoHiJLb/gYYqDnxufGmuqBeAoIv6HBq9pd
 KgYBFi/WApKiFe4A1nUCzQ==

<SEC-DOCUMENT>0001002106-04-000004.txt : 20040303
<SEC-HEADER>0001002106-04-000004.hdr.sgml : 20040303
<ACCEPTANCE-DATETIME>20040303175409
ACCESSION NUMBER:		0001002106-04-000004
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20031029
FILED AS OF DATE:		20040303

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			DIAGNOSTIC PRODUCTS CORP
		CENTRAL INDEX KEY:			0000702259
		STANDARD INDUSTRIAL CLASSIFICATION:	IN VITRO & IN VIVO DIAGNOSTIC SUBSTANCES [2835]
		IRS NUMBER:				952802182
		STATE OF INCORPORATION:			CA
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		5700 W 96TH ST
		CITY:			LOS ANGELES
		STATE:			CA
		ZIP:			90045
		BUSINESS PHONE:		3106458200

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			ARNOLD NICOLAAS
		CENTRAL INDEX KEY:			0001212371

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-09957
		FILM NUMBER:		04647016

	BUSINESS ADDRESS:	
		STREET 1:		C/O DIAGNOSTIC PRODUCTS CORP
		STREET 2:		5700 WEST 96TH ST
		CITY:			LOS ANGELES
		STATE:			CA
		ZIP:			9045
		BUSINESS PHONE:		3106458200

	MAIL ADDRESS:	
		STREET 1:		DIAGNOSTIC PRODUCTS CORP
		STREET 2:		5700 WEST 96TH STREET
		CITY:			LOS ANGELES
		STATE:			CA
		ZIP:			90045
</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>2003-10-29</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000702259</issuerCik>
        <issuerName>DIAGNOSTIC PRODUCTS CORP</issuerName>
        <issuerTradingSymbol>DP</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001212371</rptOwnerCik>
            <rptOwnerName>ARNOLD NICOLAAS</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>DIAGNOSTIC PRODUCTS CORP</rptOwnerStreet1>
            <rptOwnerStreet2>5700 WEST 96TH STREET</rptOwnerStreet2>
            <rptOwnerCity>LOS ANGELES</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>90045</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Vice President</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2003-10-29</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>M</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>7000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>17.06</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>7000</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2003-10-29</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>7000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>40</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>0</value>
                    <footnoteId id="F1"/>
                    <footnoteId id="F2"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">800 shares, Indirect, By wife, beneficial interest disclaimed</footnote>
        <footnote id="F2">Amendment to correct End of Period holdings</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>Nicolaas Arnold</signatureName>
        <signatureDate>2004-03-03</signatureDate>
    </ownerSignature>
</ownershipDocument>

</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
-----END PRIVACY-ENHANCED MESSAGE-----