-----BEGIN PRIVACY-ENHANCED MESSAGE-----
Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
Originator-Key-Asymmetric:
 MFgwCgYEVQgBAQICAf8DSgAwRwJAW2sNKK9AVtBzYZmr6aGjlWyK3XmZv3dTINen
 TWSM7vrzLADbmYQaionwg5sDW3P6oaM5D3tdezXMm7z1T+B+twIDAQAB
MIC-Info: RSA-MD5,RSA,
 I49l4kV7I+u+10muu8dPH1cwRTd2KTctHV6EF1ibHokoqA8yVmqpQ9TbL989rWtq
 BmCg4EGqqLnE+l3jAutR5A==

<SEC-DOCUMENT>0001018099-04-000006.txt : 20040108
<SEC-HEADER>0001018099-04-000006.hdr.sgml : 20040108
<ACCEPTANCE-DATETIME>20040108170505
ACCESSION NUMBER:		0001018099-04-000006
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20040106
FILED AS OF DATE:		20040108

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			MILLENNIUM CHEMICALS INC
		CENTRAL INDEX KEY:			0001018099
		STANDARD INDUSTRIAL CLASSIFICATION:	INDUSTRIAL INORGANIC CHEMICALS [2810]
		IRS NUMBER:				223436215
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		20 WIGHT AVENUE
		STREET 2:		SUITE 100
		CITY:			HUNT VALLEY
		STATE:			MD
		ZIP:			21030
		BUSINESS PHONE:		410-229-4400

	MAIL ADDRESS:	
		STREET 1:		20 WIGHT AVENUE
		STREET 2:		SUITE 100
		CITY:			HUNT VALLEY
		STATE:			MD
		ZIP:			21030

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			CLARK WORLEY H JR
		CENTRAL INDEX KEY:			0001014814

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-12091
		FILM NUMBER:		04516010

	BUSINESS ADDRESS:	
		STREET 1:		W. H. CLARK & ASSOCIATES
		STREET 2:		20 SOUTH CLARK STREET, SUITE 2222
		CITY:			CHICAGO
		STATE:			IL
		ZIP:			60603-4203
		BUSINESS PHONE:		3125807832

	MAIL ADDRESS:	
		STREET 1:		W. H. CLARK & ASSOCIATES
		STREET 2:		20 SOUTH CLARK STREET, SUITE 2222
		CITY:			CHICAGO
		STATE:			IL
		ZIP:			60603-4203
</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>2004-01-06</periodOfReport>


    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001018099</issuerCik>
        <issuerName>MILLENNIUM CHEMICALS INC</issuerName>
        <issuerTradingSymbol>MCH</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001014814</rptOwnerCik>
            <rptOwnerName>CLARK WORLEY H JR</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>W. H. CLARK &amp; ASSOCIATES</rptOwnerStreet1>
            <rptOwnerStreet2>20 SOUTH CLARK STREET, SUITE 2222</rptOwnerStreet2>
            <rptOwnerCity>CHICAGO</rptOwnerCity>
            <rptOwnerState>IL</rptOwnerState>
            <rptOwnerZipCode>60603-4203</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 $0.01 par value/share</value>
            </securityTitle>
            <transactionDate>
                <value>2004-01-06</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>986</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>12.68</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>14298</value>
                    <footnoteId id="F1"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>

    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">Represents the total number of shares directly owned by the Reporting Person of which 986 shares were issued on January 6, 2004 under the Company's Omnibus Incentive Plan in partial payment of annual Chairman of the Board fee.</footnote>
    </footnotes>


    <ownerSignature>
        <signatureName>Worley H. Clark, Jr.</signatureName>
        <signatureDate>2004-01-08</signatureDate>
    </ownerSignature>

</ownershipDocument>

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