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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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 rvgdcj0FopWoMqaz11KHRg==

<SEC-DOCUMENT>0001169232-03-005698.txt : 20030912
<SEC-HEADER>0001169232-03-005698.hdr.sgml : 20030912
<ACCEPTANCE-DATETIME>20030912143650
ACCESSION NUMBER:		0001169232-03-005698
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20030910
FILED AS OF DATE:		20030912

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

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			JDS CAPITAL MANAGEMENT INC
		CENTRAL INDEX KEY:			0001097562
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-16852
		FILM NUMBER:		03893637

	BUSINESS ADDRESS:	
		STREET 1:		780 THIRD AVENUE 45TH FLOOR
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10017
		BUSINESS PHONE:		2128339921

	MAIL ADDRESS:	
		STREET 1:		780 THIRD AVENUE 45TH FLOOR
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10017
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>d03-56935_ex.xml
<TEXT>
<XML>
<?xml version="1.0"?>
<!-- - EDGAR Ease Plus 1.0                                   07/25/03  TT    -->
<ownershipDocument>
    <schemaVersion>X0201</schemaVersion>

    <documentType>4</documentType>
   <periodOfReport>2003-09-10</periodOfReport>
   <notSubjectToSection16>0</notSubjectToSection16>
    <issuer>
        <issuerCik>0000813347</issuerCik>
        <issuerName>KOMAG INC /DE/</issuerName>
        <issuerTradingSymbol>KOMG</issuerTradingSymbol>
   </issuer>
   <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001097562</rptOwnerCik>
            <rptOwnerName>JDS CAPITAL MANAGEMENT INC</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>780 THIRD AVENUE 45TH FLOOR</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10017</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</value>
      </securityTitle>
      <transactionDate>
         <value>2003-09-10</value>
      </transactionDate>
      <transactionCoding>
         <transactionFormType>4</transactionFormType>
         <transactionCode>S</transactionCode>
         <equitySwapInvolved>0</equitySwapInvolved>
      </transactionCoding>
      <transactionAmounts>
         <transactionShares>
           <value>11828</value>
         </transactionShares>
         <transactionPricePerShare>
           <value>16.5002</value>
         </transactionPricePerShare>
         <transactionAcquiredDisposedCode>
           <value>D</value>
         </transactionAcquiredDisposedCode>
      </transactionAmounts>
      <postTransactionAmounts>
         <sharesOwnedFollowingTransaction>
           <value>3664796</value>
            <footnoteId id="F1"/>
         </sharesOwnedFollowingTransaction>
      </postTransactionAmounts>
      <ownershipNature>
         <directOrIndirectOwnership>
            <value>I</value>
         </directOrIndirectOwnership>
         <natureOfOwnership>
            <value>--</value>
            <footnoteId id="F1"/>
         </natureOfOwnership>
      </ownershipNature>
   </nonDerivativeTransaction>
   <nonDerivativeTransaction>
      <securityTitle>
         <value>Common Stock</value>
      </securityTitle>
      <transactionDate>
         <value>2003-09-10</value>
      </transactionDate>
      <transactionCoding>
         <transactionFormType>4</transactionFormType>
         <transactionCode>S</transactionCode>
         <equitySwapInvolved>0</equitySwapInvolved>
      </transactionCoding>
      <transactionAmounts>
         <transactionShares>
           <value>16000</value>
         </transactionShares>
         <transactionPricePerShare>
           <value>16.1999</value>
         </transactionPricePerShare>
         <transactionAcquiredDisposedCode>
           <value>D</value>
         </transactionAcquiredDisposedCode>
      </transactionAmounts>
      <postTransactionAmounts>
         <sharesOwnedFollowingTransaction>
           <value>3648796</value>
            <footnoteId id="F1"/>
         </sharesOwnedFollowingTransaction>
      </postTransactionAmounts>
      <ownershipNature>
         <directOrIndirectOwnership>
            <value>I</value>
         </directOrIndirectOwnership>
         <natureOfOwnership>
            <value>--</value>
            <footnoteId id="F1"/>
         </natureOfOwnership>
      </ownershipNature>
   </nonDerivativeTransaction>
 </nonDerivativeTable>
   <footnotes>
      <footnote id="F1"> These securities are being filed as part of a group consisting of JDS Capital, L.P., JDS Capital Management, LLC, J&amp;G, LLC and Joseph D. Samberg. These securities are owned directly by JDS Capital, L.P., J&amp;G, LLC and Joseph D. Samberg. These securities may be deemed to be owned indirectly by JDS Capital Management, LLC, as the general partner of JDS Capital, L.P., and by Joseph D. Samberg, as the managing member of each of JDS Capital Management, LLC and J&amp;G, LLC. As of the date hereof, of the 3,648,796 shares of Common Stock owned directly and indirectly by this group, JDS Capital, L.P. directly owns 2,976,428 shares of Common Stock, J&amp;G, LLC directly owns 101,010 shares of Common Stock and Joseph D. Samberg directly owns 571,358 shares of Common Stock. The 27,828 shares of Common Stock disposed of were owned directly by JDS Capital, L.P.</footnote>
   </footnotes>
   <ownerSignature>
      <signatureName>/s/ Joseph D. Samberg</signatureName>
      <signatureDate>2003-09-12</signatureDate>
   </ownerSignature>
</ownershipDocument>

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</TEXT>
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