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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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 StMM5GwJJBUzqJoaAtt5QQ==

<SEC-DOCUMENT>0000882796-07-000050.txt : 20070802
<SEC-HEADER>0000882796-07-000050.hdr.sgml : 20070802
<ACCEPTANCE-DATETIME>20070802174142
ACCESSION NUMBER:		0000882796-07-000050
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20070731
FILED AS OF DATE:		20070802
DATE AS OF CHANGE:		20070802

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			BIOCRYST PHARMACEUTICALS INC
		CENTRAL INDEX KEY:			0000882796
		STANDARD INDUSTRIAL CLASSIFICATION:	BIOLOGICAL PRODUCTS (NO DIAGNOSTIC SUBSTANCES) [2836]
		IRS NUMBER:				621413174
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		2190 PARKWAY LAKE DR
		CITY:			BIRMINGHAM
		STATE:			AL
		ZIP:			35244
		BUSINESS PHONE:		2054444600

	MAIL ADDRESS:	
		STREET 1:		2190 PARKWAY LAKE DR
		CITY:			BIRMINGHAM
		STATE:			AL
		ZIP:			35244

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Stonehouse Jon P
		CENTRAL INDEX KEY:			0001385496

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-23186
		FILM NUMBER:		071021568

	BUSINESS ADDRESS:	
		BUSINESS PHONE:		205-444-4600

	MAIL ADDRESS:	
		STREET 1:		2190 PARKWAY LAKE DR
		CITY:			BIRMINGHAM
		STATE:			AL
		ZIP:			35244
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>doc.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0202</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2007-07-31</periodOfReport>

    <issuer>
        <issuerCik>0000882796</issuerCik>
        <issuerName>BIOCRYST PHARMACEUTICALS INC</issuerName>
        <issuerTradingSymbol>BCRX</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001385496</rptOwnerCik>
            <rptOwnerName>Stonehouse Jon P</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>2190 PARKWAY LAKE DRIVE</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>BIRMINGHAM</rptOwnerCity>
            <rptOwnerState>AL</rptOwnerState>
            <rptOwnerZipCode>35244-</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>CEO</officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2007-07-31</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F1"/>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>2463</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>7.055</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>52463</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">The shares were purchased through the company's employee stock purchase plan at a 15% discount of the fair market value of the stock price.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>Michael Richardson by POA</signatureName>
        <signatureDate>2007-08-02</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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