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Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
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 TWSM7vrzLADbmYQaionwg5sDW3P6oaM5D3tdezXMm7z1T+B+twIDAQAB
MIC-Info: RSA-MD5,RSA,
 Sp8TluGlWtz3X3uGtwDDZZNn7MZDgUPm+t4xsKitg2i2NAWHDagVBXZvlt9IcvuS
 lnWI28Mp3PGBBprugTABDw==

<SEC-DOCUMENT>0001127602-08-011780.txt : 20081223
<SEC-HEADER>0001127602-08-011780.hdr.sgml : 20081223
<ACCEPTANCE-DATETIME>20081223194845
ACCESSION NUMBER:		0001127602-08-011780
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20081222
FILED AS OF DATE:		20081223
DATE AS OF CHANGE:		20081223

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Erck Stanley C
		CENTRAL INDEX KEY:			0001342826

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-23186
		FILM NUMBER:		081268678

	BUSINESS ADDRESS:	
		BUSINESS PHONE:		301-556-4527

	MAIL ADDRESS:	
		STREET 1:		20 FIRSTFIELD ROAD, #250
		CITY:			GAITHERSBURG
		STATE:			MD
		ZIP:			20878

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
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>form4.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0303</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2008-12-22</periodOfReport>

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

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001342826</rptOwnerCik>
            <rptOwnerName>Erck Stanley C</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>2190 PARKWAY LAKE DR</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>BIRMINGHAM</rptOwnerCity>
            <rptOwnerState>AL</rptOwnerState>
            <rptOwnerZipCode>35244</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
        </reportingOwnerRelationship>
    </reportingOwner>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Non-Qualified Stock Option</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>1.49</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2008-12-22</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness></transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>8333</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>1.49</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <value>2009-01-22</value>
                <footnoteId id="F1"/>
            </exerciseDate>
            <expirationDate>
                <value>2018-12-22</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>8333</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>8333</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">Shares vest on a pro rata monthly basis over a period of 5 months. Options will be fully vested in May 2009 at the Annual Shareholder's Meeting.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ Michael Richardson, by power of attorney</signatureName>
        <signatureDate>2008-12-23</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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