-----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,
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 JAA4hQwSZiuZZXWHeu/LfA==

<SEC-DOCUMENT>0001140361-10-008317.txt : 20100225
<SEC-HEADER>0001140361-10-008317.hdr.sgml : 20100225
<ACCEPTANCE-DATETIME>20100225091827
ACCESSION NUMBER:		0001140361-10-008317
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20100223
FILED AS OF DATE:		20100225
DATE AS OF CHANGE:		20100225

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			RACKSPACE HOSTING, INC.
		CENTRAL INDEX KEY:			0001107694
		STANDARD INDUSTRIAL CLASSIFICATION:	SERVICES-COMPUTER PROGRAMMING, DATA PROCESSING, ETC. [7370]
		IRS NUMBER:				743016523
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		5000 WALZEM RD.
		CITY:			SAN ANTONIO
		STATE:			TX
		ZIP:			78218
		BUSINESS PHONE:		2103124000

	MAIL ADDRESS:	
		STREET 1:		5000 WALZEM RD.
		CITY:			SAN ANTONIO
		STATE:			TX
		ZIP:			78218

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	RACKSPACE INC
		DATE OF NAME CHANGE:	20080403

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	RACKSPACE MANAGED HOSTING INC
		DATE OF NAME CHANGE:	20000725

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	RACKSPACE COM INC
		DATE OF NAME CHANGE:	20000224

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			WESTON GRAHAM M
		CENTRAL INDEX KEY:			0001119355

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-34143
		FILM NUMBER:		10631724

	MAIL ADDRESS:	
		STREET 1:		425 SOLEDAD SUITE 500
		CITY:			SAN ANTONIO
		STATE:			TX
		ZIP:			78205
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>doc1.xml
<DESCRIPTION>FORM 4
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0303</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2010-02-23</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001107694</issuerCik>
        <issuerName>RACKSPACE HOSTING, INC.</issuerName>
        <issuerTradingSymbol>RAX</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001119355</rptOwnerCik>
            <rptOwnerName>WESTON GRAHAM M</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O RACKSPACE HOSTING, INC.</rptOwnerStreet1>
            <rptOwnerStreet2>5000 WALZEM ROAD</rptOwnerStreet2>
            <rptOwnerCity>SAN ANTONIO</rptOwnerCity>
            <rptOwnerState>TX</rptOwnerState>
            <rptOwnerZipCode>78218</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Chairman</officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2010-02-23</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>100000</value>
                    <footnoteId id="F5"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>19.4289</value>
                    <footnoteId id="F6"/>
                    <footnoteId id="F8"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>113825</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>Shares held by Beaulieu River Rackinvest, LP.</value>
                    <footnoteId id="F1"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2010-02-24</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>100000</value>
                    <footnoteId id="F5"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>20.0923</value>
                    <footnoteId id="F7"/>
                    <footnoteId id="F8"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>13825</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>Shares held by Beaulieu River Rackinvest, LP</value>
                    <footnoteId id="F1"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>19478564</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>Shares held by Trout, Ltd.</value>
                    <footnoteId id="F2"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>25000</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>85227</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>Shares held by the Weston Remainderman Fund.</value>
                    <footnoteId id="F3"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>91266</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>Shares held by or for the benefit of family members.</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>1242302</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>Shares held by Wittington America, Ltd.</value>
                    <footnoteId id="F4"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">Mr. Weston is the  general partner of Beaulieu River Rackinvest, LP. Mr. Weston disclaims any beneficial ownership of Beaulieu River Rackinvest, LP. except to the extent of any pecuniary interest therein.</footnote>
        <footnote id="F2">Mr. Weston is the sole owner of Knightsbridge, LC which is the general partner of Trout, Ltd.</footnote>
        <footnote id="F3">Mr. Weston's children are the beneficiaries of the Weston Remainderman Fund trust. Mr. Weston disclaims any beneficial ownership of the shares held by the trust.</footnote>
        <footnote id="F4">Mr. Weston is the sole owner of Knightsbridge, LC which is the general partner of Wittington America, Ltd. Mr. Weston disclaims any beneficial ownership of Wittington America, Ltd. except to the extent of any pecuniary interest therein.</footnote>
        <footnote id="F5">These shares were sold pursuant to Giant Partners LP Rule 10b5-1 trading plan adopted by the general partner of Beaulieu River Rackinvest LP on December 14, 2009.</footnote>
        <footnote id="F6">The prices for these sales of shares ranged from $18.93 to $19.79 per share.</footnote>
        <footnote id="F7">The prices for these sales of shares ranged from $19.49 to $19.91 per share.</footnote>
        <footnote id="F8">The registrant undertakes to provide, upon request by the SEC staff, the issuer, or a security holder of the issuer, full information regarding the number of shares purchased or sold at each separate price.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>William Alberts by Power of Attorney</signatureName>
        <signatureDate>2009-02-25</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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