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Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
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<SEC-DOCUMENT>0000716039-05-000106.txt : 20050812
<SEC-HEADER>0000716039-05-000106.hdr.sgml : 20050812
<ACCEPTANCE-DATETIME>20050812175424
ACCESSION NUMBER:		0000716039-05-000106
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20050810
FILED AS OF DATE:		20050812
DATE AS OF CHANGE:		20050812

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			GILLESPIE SAMUEL H III
		CENTRAL INDEX KEY:			0001264477

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-08483
		FILM NUMBER:		051022955

	BUSINESS ADDRESS:	
		BUSINESS PHONE:		3107267600

	MAIL ADDRESS:	
		STREET 1:		C/O UNOCAL CORP
		STREET 2:		2141 ROSENCRANS AVE. #4000
		CITY:			EL SEGUNDO
		STATE:			CA
		ZIP:			90245

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			UNOCAL CORP
		CENTRAL INDEX KEY:			0000716039
		STANDARD INDUSTRIAL CLASSIFICATION:	CRUDE PETROLEUM & NATURAL GAS [1311]
		IRS NUMBER:				953825062
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			0901

	BUSINESS ADDRESS:	
		STREET 1:		2141 ROSECRANS AVE
		STREET 2:		STE 4000
		CITY:			EL SEGUNDO
		STATE:			CA
		ZIP:			90245
		BUSINESS PHONE:		3107267600

	MAIL ADDRESS:	
		STREET 1:		2141 ROSECRANS AVE
		STREET 2:		STE 4000
		CITY:			EL SEGUNDO
		STATE:			CA
		ZIP:			90245
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>f4forgill.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0202</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2005-08-10</periodOfReport>

    <notSubjectToSection16>1</notSubjectToSection16>

    <issuer>
        <issuerCik>0000716039</issuerCik>
        <issuerName>UNOCAL CORP</issuerName>
        <issuerTradingSymbol>UCL</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001264477</rptOwnerCik>
            <rptOwnerName>GILLESPIE SAMUEL H III</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>13700 MARINA POINTE DRIVE</rptOwnerStreet1>
            <rptOwnerStreet2>APARTMENT 1804</rptOwnerStreet2>
            <rptOwnerCity>MARINA DEL REY</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>90292</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Sr VP, Chief Legal</officerTitle>
            <otherText>Officer &amp;Gen Counsel</otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock / $1.00 Par Value</value>
                <footnoteId id="F1"/>
            </securityTitle>
            <transactionDate>
                <value>2005-08-10</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>D</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>21284.</value>
                </transactionShares>
                <transactionPricePerShare>
                    <footnoteId id="F2"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>0</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Option / (Right to Buy)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>36.869</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2005-08-10</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>D</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>16360.</value>
                </transactionShares>
                <transactionPricePerShare>
                    <footnoteId id="F3"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F4"/>
            </exerciseDate>
            <expirationDate>
                <value>2014-02-10</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock / $1.00 Par Value</value>
                    <footnoteId id="F1"/>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>16360.</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>0</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
        <derivativeTransaction>
            <securityTitle>
                <value>Option / (Right to Buy)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>49.305</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2005-08-10</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>D</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>18185.</value>
                </transactionShares>
                <transactionPricePerShare>
                    <footnoteId id="F3"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F5"/>
            </exerciseDate>
            <expirationDate>
                <value>2015-02-08</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock / $1.00 Par Value</value>
                    <footnoteId id="F1"/>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>18185.</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>0</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">Pursuant to the Agreement and Plan of Merger among Unocal Corporation, Chevron Corporation and Blue Merger Sub Inc. (the &quot;Merger Agreement&quot;), each share of Unocal Corporation Common Stock issued and outstanding immediately prior to the effectiveness of the merger on August 10, 2005 (the &quot;Merger&quot;), together with the Preferred Stock Purchase Rights attached thereto, was converted into the right to receive the merger consideration specified in the Merger Agreement.</footnote>
        <footnote id="F2">In connection with the Merger, the reporting person is entitled to receive merger consideration in both cash and/or stock of Chevron Corporation for Unocal stock owned, subject to election and proration. Based on a press release issued by Chevron on August 10, 2005 announcing preliminary results of elections for merger consideration, and valuing Chevron shares at the closing price of $62.48 on August 10, 2005, the estimated value of the merger consideration to be received by the reporting person in exchange for these shares  is between $1,369,719 and $1,436,136, depending upon the election made and the final election and proration results.</footnote>
        <footnote id="F3">This option was assumed by Chevron Corporation pursuant to the  Merger Agreement, and converted into an option to purchase a revised number of Chevron Corporation common shares (determined by multiplying the number of shares of Unocal Common Stock subject to the option by the Stock Award Exchange Ratio, rounded down to the nearest whole share) at a new exercise price (determined by dividing the exercise price per share of Unocal Common Stock subject to the option by the Stock Award Exchange Ratio, rounded up to the nearest one hundredth of a cent).  The Stock Award Exchange Ratio is 1.0688331.</footnote>
        <footnote id="F4">The stock option was originally scheduled to become exercisable in three equal annual
installments on 2-10-2005, 2-10-2006 and 2-10-2007.  The entire option became exercisable upon effectiveness of the merger on August 10, 2005.</footnote>
        <footnote id="F5">The option was originally scheduled to become exercisable in three equal installments on 2/8/2006, 2/8/2007 and 2/8/2008.  The entire option became exercisable upon the effectiveness of the merger August 10, 2005.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>Paul R. Moore, Ass't Secretary, Attorney-in-fact</signatureName>
        <signatureDate>2005-08-12</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
-----END PRIVACY-ENHANCED MESSAGE-----