-----BEGIN PRIVACY-ENHANCED MESSAGE-----
Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
Originator-Key-Asymmetric:
 MFgwCgYEVQgBAQICAf8DSgAwRwJAW2sNKK9AVtBzYZmr6aGjlWyK3XmZv3dTINen
 TWSM7vrzLADbmYQaionwg5sDW3P6oaM5D3tdezXMm7z1T+B+twIDAQAB
MIC-Info: RSA-MD5,RSA,
 Sp9uzSrlXRlBL/v56HH6ZO5xGYXvhkhjb2AfodrBhusOPCtvR+TFUdAQV+NK9oWr
 6SnavrBHY0kyX1aYkeFg9w==

<SEC-DOCUMENT>0001179110-04-015893.txt : 20040804
<SEC-HEADER>0001179110-04-015893.hdr.sgml : 20040804
<ACCEPTANCE-DATETIME>20040804192513
ACCESSION NUMBER:		0001179110-04-015893
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20040803
FILED AS OF DATE:		20040804

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			NUVASIVE INC
		CENTRAL INDEX KEY:			0001142596
		STANDARD INDUSTRIAL CLASSIFICATION:	SURGICAL & MEDICAL INSTRUMENTS & APPARATUS [3841]
		IRS NUMBER:				330768598
		STATE OF INCORPORATION:			DE

	BUSINESS ADDRESS:	
		STREET 1:		10065 OLD GROVE RD
		CITY:			SAN DIEGO
		STATE:			CA
		ZIP:			92131
		BUSINESS PHONE:		8582717070

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			BLAIR JACK R
		CENTRAL INDEX KEY:			0001183883

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-50744
		FILM NUMBER:		04952872

	BUSINESS ADDRESS:	
		STREET 1:		5677 AIRLINE ROAD
		CITY:			ARLINGTON
		STATE:			TN
		ZIP:			38002
		BUSINESS PHONE:		9018679971

	MAIL ADDRESS:	
		STREET 1:		3800 FORREST HILL-IRENE ROAD,
		STREET 2:		SUITE 100
		CITY:			MEMPHIS
		STATE:			TN
		ZIP:			38125
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>edgar.xml
<DESCRIPTION>FORM 4 -
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0202</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2004-08-03</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001142596</issuerCik>
        <issuerName>NUVASIVE INC</issuerName>
        <issuerTradingSymbol>NUVA</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001183883</rptOwnerCik>
            <rptOwnerName>BLAIR JACK R</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>10065 OLD GROVE ROAD</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>SAN DIEGO</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>92131</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2004-08-03</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>1500</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>10.05</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>1500</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes></footnotes>

    <ownerSignature>
        <signatureName>/s/  Kevin O'Boyle, by power of attorney</signatureName>
        <signatureDate>2004-08-03</signatureDate>
    </ownerSignature>
</ownershipDocument>

</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
-----END PRIVACY-ENHANCED MESSAGE-----