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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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 eNsgznnwxFhGBXQ1sAq6oA==

<SEC-DOCUMENT>0001005477-04-004163.txt : 20041119
<SEC-HEADER>0001005477-04-004163.hdr.sgml : 20041119
<ACCEPTANCE-DATETIME>20041119163905
ACCESSION NUMBER:		0001005477-04-004163
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20041117
FILED AS OF DATE:		20041119
DATE AS OF CHANGE:		20041119

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			FEINBERG STEPHEN
		CENTRAL INDEX KEY:			0000947822
		STATE OF INCORPORATION:			NY
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-16852
		FILM NUMBER:		041158295

	BUSINESS ADDRESS:	
		BUSINESS PHONE:		2128912120

	MAIL ADDRESS:	
		STREET 1:		450 PARK AVE
		STREET 2:		28TH FL
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10022

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			KOMAG INC /DE/
		CENTRAL INDEX KEY:			0000813347
		STANDARD INDUSTRIAL CLASSIFICATION:	MAGNETIC & OPTICAL RECORDING MEDIA [3695]
		IRS NUMBER:				942914864
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			0102

	BUSINESS ADDRESS:	
		STREET 1:		1710 AUTOMATION PWY
		CITY:			SAN JOSE
		STATE:			CA
		ZIP:			95131
		BUSINESS PHONE:		4085762000

	MAIL ADDRESS:	
		STREET 1:		1710 AUTOMATION PWY
		CITY:			SAN JOSE
		STATE:			CA
		ZIP:			95131
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>edgar123.xml
<DESCRIPTION>FORM 4
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0202</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2004-11-17</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000813347</issuerCik>
        <issuerName>KOMAG INC /DE/</issuerName>
        <issuerTradingSymbol>KOMG</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0000947822</rptOwnerCik>
            <rptOwnerName>FEINBERG STEPHEN</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O CERBERUS CAPITAL MANAGEMENT, L.P.</rptOwnerStreet1>
            <rptOwnerStreet2>299 PARK AVENUE - 22ND FLOOR</rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10171</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock, par value $0.01 per share</value>
            </securityTitle>
            <transactionDate>
                <value>2004-11-17</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>10000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>17.15</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>3686100</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                    <footnoteId id="F1"/>
                    <footnoteId id="F2"/>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By partnerships, corporations and companies</value>
                    <footnoteId id="F1"/>
                    <footnoteId id="F2"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">As of November 17, 2004, Cerberus Partners, L.P., a Delaware limited partnership (&quot;Cerberus&quot;), is the holder of 361,737 shares of the common stock (the &quot;Shares&quot;) of Komag, Incorporated (the &quot;Company&quot;), Cerberus International, Ltd., a corporation organized under the laws of the Bahamas (&quot;International&quot;), is the holder of 1,915,937 Shares, Cerberus Series One Holdings, LLC, a Delaware limited liability company (&quot;Cerberus Series One&quot;), is the holder of 827,566 Shares, Cerberus Series Two Holdings, LLC, a Delaware limited liability company (&quot;Cerberus Series Two&quot;), is the holder of 492,153 Shares, and Cerberus America Series One Holdings, LLC, a Delaware limited liability company (&quot;Cerberus America&quot;), is the holder of 88,707 Shares.  Stephen Feinberg possesses sole power to vote and direct the disposition of all securities of the Company owned by each of Cerberus, International, Cerberus Series One, Cerberus Series Two
 and Cerberus America.</footnote>
        <footnote id="F2">Thus, for the purposes of Reg. Section 240.13d-3, Stephen Feinberg is deemed to beneficially own 3,686,100 Shares.  Stephen Feinberg's interest in the securities reported herein is limited to the extent of his pecuniary interest in Cerberus, International, Cerberus Series One, Cerberus Series Two and Cerberus America, respectively, if any.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ Stephen Feinberg</signatureName>
        <signatureDate>2004-11-18</signatureDate>
    </ownerSignature>
</ownershipDocument>

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