-----BEGIN PRIVACY-ENHANCED MESSAGE-----
Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
Originator-Key-Asymmetric:
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 TWSM7vrzLADbmYQaionwg5sDW3P6oaM5D3tdezXMm7z1T+B+twIDAQAB
MIC-Info: RSA-MD5,RSA,
 DcK2tGXH2tk61eF06auhZF614nTTseQc4wy+r1ij5evcOqrqP47NGviH3LkRpTZj
 iMipyHsgyYhC820KKXXWEg==

<SEC-DOCUMENT>0001179110-04-010914.txt : 20040519
<SEC-HEADER>0001179110-04-010914.hdr.sgml : 20040519
<ACCEPTANCE-DATETIME>20040519161424
ACCESSION NUMBER:		0001179110-04-010914
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20040517
FILED AS OF DATE:		20040519

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			MARKWEST HYDROCARBON INC
		CENTRAL INDEX KEY:			0001019756
		STANDARD INDUSTRIAL CLASSIFICATION:	CRUDE PETROLEUM & NATURAL GAS [1311]
		IRS NUMBER:				841352233
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		155 INVERNESS DRIVE WEST
		STREET 2:		SUITE 200
		CITY:			ENGLEWOOD
		STATE:			CO
		ZIP:			80112-5004
		BUSINESS PHONE:		3032908700

	MAIL ADDRESS:	
		STREET 1:		155 INVERNESS DRIVE WEST
		STREET 2:		SUITE 200
		CITY:			ENGLEWOOD
		STATE:			CO
		ZIP:			80112-5004

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			MARKWEST HOLDING CO
		CENTRAL INDEX KEY:			0001286296
		STATE OF INCORPORATION:			CO

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-14841
		FILM NUMBER:		04818815

	BUSINESS ADDRESS:	
		STREET 1:		155 INVERNESS DR WEST
		CITY:			ENGLEWOOD
		STATE:			CO
		ZIP:			80112
		BUSINESS PHONE:		3032908700

	MAIL ADDRESS:	
		STREET 1:		155 INVERNESS DR WEST
		CITY:			ENGLEWOOD
		STATE:			CO
		ZIP:			80112
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>edgar.xml
<DESCRIPTION>FORM 4 -
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0202</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2004-05-17</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001019756</issuerCik>
        <issuerName>MARKWEST HYDROCARBON INC</issuerName>
        <issuerTradingSymbol>MWP</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001286296</rptOwnerCik>
            <rptOwnerName>MARKWEST HOLDING CO</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O MARKWEST HYDROCARBON, INC.</rptOwnerStreet1>
            <rptOwnerStreet2>155 INVERNESS DRIVE WEST, STE 200</rptOwnerStreet2>
            <rptOwnerCity>ENGLEWOOD</rptOwnerCity>
            <rptOwnerState>CO</rptOwnerState>
            <rptOwnerZipCode>80112</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2004-05-17</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>6000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>11.05</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>4086194</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes></footnotes>

    <ownerSignature>
        <signatureName>Lucy Woods POA for John M Fox, Director of MWHC Holding, Inc.</signatureName>
        <signatureDate>2004-05-19</signatureDate>
    </ownerSignature>
</ownershipDocument>

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