-----BEGIN PRIVACY-ENHANCED MESSAGE-----
Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
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MIC-Info: RSA-MD5,RSA,
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 mqD1tk0FQepZc6/XCRhqNg==

<SEC-DOCUMENT>0001181431-07-029844.txt : 20070504
<SEC-HEADER>0001181431-07-029844.hdr.sgml : 20070504
<ACCEPTANCE-DATETIME>20070504155537
ACCESSION NUMBER:		0001181431-07-029844
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20070503
FILED AS OF DATE:		20070504
DATE AS OF CHANGE:		20070504

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			OCONNOR SHAWN
		CENTRAL INDEX KEY:			0001227877

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-31253
		FILM NUMBER:		07820380

	BUSINESS ADDRESS:	
		STREET 1:		C/O PHARSIGHT
		STREET 2:		8OO WEST EL CAMINO REAL STE 200
		CITY:			MOUNTAIN VIEW
		STATE:			CA
		ZIP:			94040
		BUSINESS PHONE:		6503143817

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			PHARSIGHT CORP
		CENTRAL INDEX KEY:			0001040853
		STANDARD INDUSTRIAL CLASSIFICATION:	SERVICES-PREPACKAGED SOFTWARE [7372]
		IRS NUMBER:				770401273
		STATE OF INCORPORATION:			CA
		FISCAL YEAR END:			0331

	BUSINESS ADDRESS:	
		STREET 1:		321 E. EVELYN AVENUE
		STREET 2:		3RD FLOOR
		CITY:			MOUNTAIN VIEW
		STATE:			CA
		ZIP:			94041
		BUSINESS PHONE:		6503143800

	MAIL ADDRESS:	
		STREET 1:		321 E. EVELYN AVENUE
		STREET 2:		3RD FLOOR
		CITY:			MOUNTAIN VIEW
		STATE:			CA
		ZIP:			94041
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>rrd157110.xml
<DESCRIPTION>FORM 4
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0202</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2007-05-03</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001040853</issuerCik>
        <issuerName>PHARSIGHT CORP</issuerName>
        <issuerTradingSymbol>PHST</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001227877</rptOwnerCik>
            <rptOwnerName>OCONNOR SHAWN</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O PHARSIGHT CORPORATION</rptOwnerStreet1>
            <rptOwnerStreet2>321 E. EVELYN AVENUE, 3RD FLOOR</rptOwnerStreet2>
            <rptOwnerCity>MOUNTAIN VIEW</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>94041</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>President and CEO</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Incentive Stock Option (right to buy)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>1.75</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2007-05-03</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>125000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <value>2008-05-03</value>
                <footnoteId id="F1"/>
            </exerciseDate>
            <expirationDate>
                <value>2017-05-03</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>125000</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>125000</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">25% of the shares subject to the option will vest and become exercisable on May 3, 2008, and the remaining shares will vest monthly thereafter, such that 100% of the shares subject to the option will be fully vested and exercisable on May 3, 2011. The option has a 100% acceleration clause in the event of a change in control.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>Quynh Trinh, Attorney-in-fact for Shawn O'Connor</signatureName>
        <signatureDate>2007-05-04</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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