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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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 Hn8WpojzOCFou5NSyVN04Q==

<SEC-DOCUMENT>0001181431-09-058575.txt : 20091223
<SEC-HEADER>0001181431-09-058575.hdr.sgml : 20091223
<ACCEPTANCE-DATETIME>20091223173751
ACCESSION NUMBER:		0001181431-09-058575
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20091222
FILED AS OF DATE:		20091223
DATE AS OF CHANGE:		20091223

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Sherif Tarek
		CENTRAL INDEX KEY:			0001466275

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-34387
		FILM NUMBER:		091259121

	MAIL ADDRESS:	
		STREET 1:		C/O MEDIDATA SOLUTIONS, INC.
		STREET 2:		79 FIFTH AVENUE, 8TH FLOOR
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10003

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			Medidata Solutions, Inc.
		CENTRAL INDEX KEY:			0001453814
		STANDARD INDUSTRIAL CLASSIFICATION:	SERVICES-PREPACKAGED SOFTWARE [7372]
		IRS NUMBER:				522319066
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		79 FIFTH AVENUE, 8TH FLOOR
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10003
		BUSINESS PHONE:		212.918.1800

	MAIL ADDRESS:	
		STREET 1:		79 FIFTH AVENUE, 8TH FLOOR
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10003
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>rrd260546.xml
<DESCRIPTION>FORM 4 - TAREK SHERIF
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0303</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2009-12-22</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001453814</issuerCik>
        <issuerName>Medidata Solutions, Inc.</issuerName>
        <issuerTradingSymbol>MDSO</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001466275</rptOwnerCik>
            <rptOwnerName>Sherif Tarek</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O MEDIDATA SOLUTIONS, INC.</rptOwnerStreet1>
            <rptOwnerStreet2>79 FIFTH AVENUE, 8TH FLOOR</rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10003</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Chairman &amp; CEO</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2009-12-22</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>F</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>2272</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>15.05</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>1092934</value>
                    <footnoteId id="F2"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">Shares withheld by Medidata to satisfy the tax withholding obligation in connection with the vesting of previously awarded restricted stock.</footnote>
        <footnote id="F2">Since the date of the reporting person's last ownership report, he transferred  243,000 shares to his ex-wife pursuant to a domestic relations order.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ Michael I. Otner, Attorney-in-Fact</signatureName>
        <signatureDate>2009-12-23</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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