-----BEGIN PRIVACY-ENHANCED MESSAGE-----
Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
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MIC-Info: RSA-MD5,RSA,
 M2CZvGZxSirE/1+BYG6cc4oK0cjMMNJWEnHg5l//JoE6bL7yCmSunCOnMvwLg0G3
 inDgpVd8Cca6T76CyvRPCg==

<SEC-DOCUMENT>0000921895-09-002011.txt : 20090717
<SEC-HEADER>0000921895-09-002011.hdr.sgml : 20090717
<ACCEPTANCE-DATETIME>20090717192105
ACCESSION NUMBER:		0000921895-09-002011
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20090715
FILED AS OF DATE:		20090717
DATE AS OF CHANGE:		20090717

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			ADAPTEC INC
		CENTRAL INDEX KEY:			0000709804
		STANDARD INDUSTRIAL CLASSIFICATION:	COMPUTER COMMUNICATIONS EQUIPMENT [3576]
		IRS NUMBER:				942748530
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			0331

	BUSINESS ADDRESS:	
		STREET 1:		691 S MILPITAS BLVD
		STREET 2:		M/S25
		CITY:			MILPITAS
		STATE:			CA
		ZIP:			95035
		BUSINESS PHONE:		4089458600

	MAIL ADDRESS:	
		STREET 1:		691 SOUTH MILPITAS BLVD
		STREET 2:		M/S25
		CITY:			MILPITAS
		STATE:			CA
		ZIP:			95035

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			STEEL PARTNERS II LP
		CENTRAL INDEX KEY:			0000915653

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-15071
		FILM NUMBER:		09951805

	BUSINESS ADDRESS:	
		STREET 1:		590 MADISON AVENUE
		STREET 2:		32ND FLOOR
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10022
		BUSINESS PHONE:		212-758-3232

	MAIL ADDRESS:	
		STREET 1:		590 MADISON AVENUE, 32ND FLOOR
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10022

	FORMER NAME:	
		FORMER CONFORMED NAME:	STEEL PARTNERS II L P
		DATE OF NAME CHANGE:	19950627

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			LICHTENSTEIN WARREN G
		CENTRAL INDEX KEY:			0001005784
		STATE OF INCORPORATION:			NY
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-15071
		FILM NUMBER:		09951803

	MAIL ADDRESS:	
		STREET 1:		C/O STEEL PARTNERS II L P
		STREET 2:		590 MADISON AVENUE, 32ND FLOOR
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10022

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			STEEL PARTNERS II GP LLC
		CENTRAL INDEX KEY:			0001262861

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-15071
		FILM NUMBER:		09951801

	BUSINESS ADDRESS:	
		STREET 1:		590 MADISON AVENUE, 32ND FLOOR
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10022
		BUSINESS PHONE:		212-758-3232

	MAIL ADDRESS:	
		STREET 1:		590 MADISON AVENUE, 32ND FLOOR
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10022

	FORMER NAME:	
		FORMER CONFORMED NAME:	STEEL PARTNERS LLC
		DATE OF NAME CHANGE:	20030908

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Steel Partners LLC
		CENTRAL INDEX KEY:			0001422282

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-15071
		FILM NUMBER:		09951804

	BUSINESS ADDRESS:	
		STREET 1:		590 MADISON AVENUE, 32ND FLOOR
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10022
		BUSINESS PHONE:		212-520-2300

	MAIL ADDRESS:	
		STREET 1:		590 MADISON AVENUE, 32ND FLOOR
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10022

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			STEEL PARTNERS HOLDINGS L.P.
		CENTRAL INDEX KEY:			0001452857
		STATE OF INCORPORATION:			DE

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-15071
		FILM NUMBER:		09951802

	BUSINESS ADDRESS:	
		STREET 1:		590 MADISON AVENUE, 32ND FLOOR
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10022
		BUSINESS PHONE:		212-520-2300

	MAIL ADDRESS:	
		STREET 1:		590 MADISON AVENUE, 32ND FLOOR
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10022

	FORMER NAME:	
		FORMER CONFORMED NAME:	WEBFINANCIAL L.P.
		DATE OF NAME CHANGE:	20081229
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>ste101.xml
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0303</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2009-07-15</periodOfReport>

    <notSubjectToSection16>1</notSubjectToSection16>

    <issuer>
        <issuerCik>0000709804</issuerCik>
        <issuerName>ADAPTEC INC</issuerName>
        <issuerTradingSymbol>ADPT</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0000915653</rptOwnerCik>
            <rptOwnerName>STEEL PARTNERS II LP</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>590 MADISON AVENUE, 32ND FLOOR</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10022</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001422282</rptOwnerCik>
            <rptOwnerName>Steel Partners LLC</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O STEEL PARTNERS II, L.P.</rptOwnerStreet1>
            <rptOwnerStreet2>590 MADISON AVENUE, 32ND FLOOR</rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10022</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001005784</rptOwnerCik>
            <rptOwnerName>LICHTENSTEIN WARREN G</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O STEEL PARTNERS II, L.P.</rptOwnerStreet1>
            <rptOwnerStreet2>590 MADISON AVENUE, 32ND FLOOR</rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10022</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001452857</rptOwnerCik>
            <rptOwnerName>STEEL PARTNERS HOLDINGS L.P.</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O STEEL PARTNERS II, L.P.</rptOwnerStreet1>
            <rptOwnerStreet2>590 MADISON AVENUE, 32ND FLOOR</rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10022</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001262861</rptOwnerCik>
            <rptOwnerName>STEEL PARTNERS II GP LLC</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O STEEL PARTNERS II, L.P.</rptOwnerStreet1>
            <rptOwnerStreet2>590 MADISON AVENUE, 32ND FLOOR</rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10022</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, $.001 Par Value</value>
            </securityTitle>
            <transactionDate>
                <value>2009-07-15</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>J</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F1"/>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>13034132</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>10137206</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                    <footnoteId id="F2"/>
                    <footnoteId id="F3"/>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">Transaction constitutes a distribution of shares to indirect investors of Steel Partners II, L.P.</footnote>
        <footnote id="F2">This Form 4 is filed jointly by Steel Partners II, L.P. (&quot;Steel Partners II&quot;), Steel Partners Holdings L.P. (formerly known as WebFinancial L.P.) (&quot;Steel Holdings&quot;), Steel Partners LLC (&quot;Partners LLC&quot;), Steel Partners II GP LLC (&quot;Steel Partners GP&quot;) and Warren G. Lichtenstein.</footnote>
        <footnote id="F3">The securities reported in this Form 4 are owned directly by Steel Partners II, and owned indirectly by Steel Holdings by virtue of it being the sole limited partner of Steel Partners II, by Partners LLC by virtue of it being the manager of Steel Partners II and Steel Holdings, by Steel Partners GP by virtue of it being the general partner of Steel Partners II and Steel Holdings and by Mr. Lichtenstein by virtue of his position as the manager of Partners LLC and the managing member of Steel Partners GP. Steel Holdings, Partners LLC, Steel Partners GP and Mr. Lichtenstein disclaim beneficial ownership of the shares owned by Steel Partners II except to the extent of their pecuniary interest therein.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>By: Steel Partners II, L.P., By: Steel Partners II GP LLC, General Partner, By: /s/ Sanford Antignas, as Attorney in Fact for Warren G. Lichtenstein, Managing Member</signatureName>
        <signatureDate>2009-07-17</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>By: Steel Partners LLC, By: /s/ Sanford Antignas, as Attorney In Fact for Warren G. Lichtenstein, Manager</signatureName>
        <signatureDate>2009-07-17</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>By: By: /s/ Sanford Antignas, as Attorney in Fact for Warren G. Lichtenstein</signatureName>
        <signatureDate>2009-07-17</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>By: Steel Partners Holdings L.P., By: Steel Partners II GP LLC, General Partner, By: /s/ Sanford Antignas, as Attorney In Fact for Warren G. Lichtenstein, Managing Member</signatureName>
        <signatureDate>2009-07-17</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>By: Steel Partners II GP LLC, By: /s/ Sanford Antignas, as Attorney In Fact for Warren G. Lichtenstein, Managing Member</signatureName>
        <signatureDate>2009-07-17</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
-----END PRIVACY-ENHANCED MESSAGE-----