-----BEGIN PRIVACY-ENHANCED MESSAGE-----
Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
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 TWSM7vrzLADbmYQaionwg5sDW3P6oaM5D3tdezXMm7z1T+B+twIDAQAB
MIC-Info: RSA-MD5,RSA,
 PhjEDndyKDd7iHtF0GLPnRmNpDRTvgPeyqnoLVH5Ullrj/OXJbJdmfxtj37xKk+R
 9r2vZImyRVmsQLe6TPpBYA==

<SEC-DOCUMENT>0001005477-09-002353.txt : 20090518
<SEC-HEADER>0001005477-09-002353.hdr.sgml : 20090518
<ACCEPTANCE-DATETIME>20090518171632
ACCESSION NUMBER:		0001005477-09-002353
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20090514
FILED AS OF DATE:		20090518
DATE AS OF CHANGE:		20090518

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Li Kai
		CENTRAL INDEX KEY:			0001402353

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-33517
		FILM NUMBER:		09837471

	MAIL ADDRESS:	
		STREET 1:		C/O DATA DOMAIN, INC.
		STREET 2:		2300 CENTRAL EXPRESSWAY
		CITY:			SANTA CLARA
		STATE:			CA
		ZIP:			95050

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			Data Domain, Inc.
		CENTRAL INDEX KEY:			0001391984
		STANDARD INDUSTRIAL CLASSIFICATION:	COMPUTER STORAGE DEVICES [3572]
		IRS NUMBER:				943412175
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		2421 MISSION COLLEGE BLVD
		CITY:			SANTA CLARA
		STATE:			CA
		ZIP:			95054
		BUSINESS PHONE:		(408) 980-4800

	MAIL ADDRESS:	
		STREET 1:		2421 MISSION COLLEGE BLVD
		CITY:			SANTA CLARA
		STATE:			CA
		ZIP:			95054
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>edgar123.xml
<DESCRIPTION>FORM 4
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0303</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2009-05-14</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001391984</issuerCik>
        <issuerName>Data Domain, Inc.</issuerName>
        <issuerTradingSymbol>DDUP</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001402353</rptOwnerCik>
            <rptOwnerName>Li Kai</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O DATA DOMAIN</rptOwnerStreet1>
            <rptOwnerStreet2>2421 MISSION COLLEGE BLVD.</rptOwnerStreet2>
            <rptOwnerCity>SANTA CLARA</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>95054</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2009-05-14</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F1"/>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>7000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>16.8488</value>
                    <footnoteId id="F2"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>615459</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>121467</value>
                    <footnoteId id="F3"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By GRAT</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>150000</value>
                    <footnoteId id="F3"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By GRAT II</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>200000</value>
                    <footnoteId id="F3"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By GRAT III</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>28533</value>
                    <footnoteId id="F3"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By Trust</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">This transaction was effected pursuant to a Rule 10b5-1 plan adopted by the reporting person on May 30, 2008.</footnote>
        <footnote id="F2">Represents a weighted average sales price per share.  The prices actually received ranged from $16.66 to $17.00.  The reporting person has provided to the issuer and will provide to any security holder of the issuer or the SEC staff, upon request, information regarding the number of shares sold at each price within the range.</footnote>
        <footnote id="F3">Pursuant to the terms of the GRAT, 378,533 shares were distributed to the reporting person in his capacity as Trustee.  Of those shares, 150,000 were transferred to the Kai Li Grantor Retained Annuity Trust II, 200,000 shares were transferred to the Kai Li Grantor Retained Annuity Trust III and 28,533 shares were transferred to the Kai Li Revocable Trust dtd 12/26/07.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ Kai Li by Robert G. Specker, Attorney-in-Fact</signatureName>
        <signatureDate>2009-05-18</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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