<SUBMISSION>
<ACCESSION-NUMBER>0001181431-08-068279
<TYPE>4
<PUBLIC-DOCUMENT-COUNT>1
<PERIOD>20081216
<FILING-DATE>20081218
<DATE-OF-FILING-DATE-CHANGE>20081218
<ISSUER>
<COMPANY-DATA>
<CONFORMED-NAME>Digital Realty Trust, Inc.
<CIK>0001297996
<ASSIGNED-SIC>6798
<IRS-NUMBER>000000000
<STATE-OF-INCORPORATION>MD
<FISCAL-YEAR-END>1231
</COMPANY-DATA>
<BUSINESS-ADDRESS>
<STREET1>560 MISSION STREET
<STREET2>SUITE 2900
<CITY>SAN FRANCISCO
<STATE>CA
<ZIP>94105
<PHONE>(415)738-6500
</BUSINESS-ADDRESS>
<MAIL-ADDRESS>
<STREET1>560 MISSION STREET
<STREET2>SUITE 2900
<CITY>SAN FRANCISCO
<STATE>CA
<ZIP>94105
</MAIL-ADDRESS>
</ISSUER>
<REPORTING-OWNER>
<OWNER-DATA>
<CONFORMED-NAME>Stein A William
<CIK>0001307117
</OWNER-DATA>
<FILING-VALUES>
<FORM-TYPE>4
<ACT>34
<FILE-NUMBER>001-32336
<FILM-NUMBER>081258594
</FILING-VALUES>
<BUSINESS-ADDRESS>
<PHONE>(650) 233-3600
</BUSINESS-ADDRESS>
<MAIL-ADDRESS>
<STREET1>DIGITAL REALTY TRUST, INC.
<STREET2>2730 SAND HILL ROAD, SUITE 280
<CITY>MENLO PARK
<STATE>CA
<ZIP>94025
</MAIL-ADDRESS>
</REPORTING-OWNER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>rrd226877.xml
<DESCRIPTION>FORM 4 FOR A. WILLIAM STEIN (CONVERSION & SALE)
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0303</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2008-12-16</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001297996</issuerCik>
        <issuerName>Digital Realty Trust, Inc.</issuerName>
        <issuerTradingSymbol>DLR</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001307117</rptOwnerCik>
            <rptOwnerName>Stein A William</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>560 MISSION STREET, SUITE 2900</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>SAN FRANCISCO</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>94105</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>CFO and CIO</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2008-12-16</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>M</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F1"/>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>30000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <footnoteId id="F2"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>30000</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2008-12-16</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>30000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>30.51</value>
                    <footnoteId id="F3"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>0</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Class C Profits Interest Units</value>
                <footnoteId id="F1"/>
                <footnoteId id="F2"/>
            </securityTitle>
            <conversionOrExercisePrice>
                <footnoteId id="F4"/>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2008-12-16</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>M</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F1"/>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>30000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F2"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F5"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>30000</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>72825</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">A. William Stein converted 30,000 Class C Profits Interest Units into common limited partnership units (&quot;Common Units&quot;) of Digital Realty Trust, L.P., a Maryland Limited Partnership (the &quot;Operating Partnership&quot;), and subsequently redeemed the 30,000 Common Units for 30,000 shares of the common stock of Digital Realty Trust, Inc. (the &quot;Issuer&quot;), all in accordance with the requirements of the Limited Partnership Agreement of the Operating Partnership.</footnote>
        <footnote id="F2">Class C Units are membership interests in the Operating Partnership of which the Issuer is the general partner. Class C Units that have satisfied the performance condition and achieved full parity with Common Units receive the same quarterly distributions as Common Units, and may be converted into an equal number of Common Units on a one-for-one basis at any time. Common Units will be redeemable for cash based on the fair market value of an equivalent number of shares of the Issuer's common stock, or, at the election of the Issuer, for an equal number of shares of the Issuer's common stock. The Class C Units have achieved full parity with Common Units.</footnote>
        <footnote id="F3">Represents the average sale price. Exact sale prices range from $30.00 to 31.88.</footnote>
        <footnote id="F4">1 for 1.</footnote>
        <footnote id="F5">N/A</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ Barbara Polster, attorney-in-fact</signatureName>
        <signatureDate>2008-12-18</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SUBMISSION>
