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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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 XNm5GQ94EGvoOZFSRQa4Hw==

<SEC-DOCUMENT>0001104659-03-020156.txt : 20030905
<SEC-HEADER>0001104659-03-020156.hdr.sgml : 20030905
<ACCEPTANCE-DATETIME>20030905180348
ACCESSION NUMBER:		0001104659-03-020156
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20030904
FILED AS OF DATE:		20030905

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			NEKTAR THERAPEUTICS
		CENTRAL INDEX KEY:			0000906709
		STANDARD INDUSTRIAL CLASSIFICATION:	PHARMACEUTICAL PREPARATIONS [2834]
		IRS NUMBER:				943134940
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		150 INDUSTRIAL RD
		CITY:			SAN CARLOS
		STATE:			CA
		ZIP:			94070
		BUSINESS PHONE:		6506313100

	MAIL ADDRESS:	
		STREET 1:		150 INDUSTRIAL ROAD
		CITY:			SAN CARLOS
		STATE:			CA
		ZIP:			94070

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	INHALE THERAPEUTIC SYSTEMS INC
		DATE OF NAME CHANGE:	19980723

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	INHALE THERAPEUTIC SYSTEMS
		DATE OF NAME CHANGE:	19940303

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			BROWN MICHAEL A/CA
		CENTRAL INDEX KEY:			0001204920

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-24006
		FILM NUMBER:		03884633

	BUSINESS ADDRESS:	
		STREET 1:		C/O QUANTUM CORP
		STREET 2:		501 SYCAMORE DR
		CITY:			MILPITAS
		STATE:			CA
		ZIP:			95035
		BUSINESS PHONE:		4089444460

	MAIL ADDRESS:	
		STREET 1:		C/O QUANTUM CORP
		STREET 2:		501 SYCAORE DR
		CITY:			MILPITAS
		STATE:			CA
		ZIP:			95035
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>a4.xml
<DESCRIPTION>4
<TEXT>
<XML>
<?xml version="1.0" encoding="utf-8"?>
<ownershipDocument>
    <schemaVersion>X0201</schemaVersion>

    <documentType>4</documentType>
  <periodOfReport>2003-09-04</periodOfReport>
  <notSubjectToSection16>0</notSubjectToSection16>
    <issuer>
        <issuerCik>0000906709</issuerCik>
        <issuerName>NEKTAR THERAPEUTICS</issuerName>
        <issuerTradingSymbol>NKTR</issuerTradingSymbol>
  </issuer>
  <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001204920</rptOwnerCik>
            <rptOwnerName>BROWN MICHAEL A/CA</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O NEKTAR THERAPEUTICS</rptOwnerStreet1>
            <rptOwnerStreet2>150 INDUSTRIAL ROAD</rptOwnerStreet2>
            <rptOwnerCity>SAN CARLOS</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>94070</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
            <reportingOwnerRelationship>
      <isDirector>1</isDirector>
      <isOfficer>0</isOfficer>
      <isTenPercentOwner>0</isTenPercentOwner>
      <isOther>0</isOther>
    </reportingOwnerRelationship>
  </reportingOwner>
  <derivativeTable>
    <derivativeTransaction>
      <securityTitle>
        <value>Employee Stock Option (Right to Buy)</value>
      </securityTitle>
      <conversionOrExercisePrice>
        <value>11.41</value>
      </conversionOrExercisePrice>
      <transactionDate>
        <value>2003-09-04</value>
      </transactionDate>
      <transactionCoding>
        <transactionFormType>4</transactionFormType>
        <transactionCode>A</transactionCode>
        <equitySwapInvolved>0</equitySwapInvolved>
      </transactionCoding>
      <transactionTimeliness>
        <value></value>
      </transactionTimeliness>
      <transactionAmounts>
        <transactionShares>
          <value>12500</value>
        </transactionShares>
        <transactionPricePerShare>
          <value>0</value>
        </transactionPricePerShare>
        <transactionAcquiredDisposedCode>
          <value>A</value>
        </transactionAcquiredDisposedCode>
      </transactionAmounts>
      <exerciseDate>
        <footnoteId id="F1"/>
      </exerciseDate>
      <expirationDate>
        <value>2013-09-04</value>
      </expirationDate>
      <underlyingSecurity>
        <underlyingSecurityTitle>
          <value>Common Stock</value>
        </underlyingSecurityTitle>
        <underlyingSecurityShares>
          <value>12500</value>
        </underlyingSecurityShares>
      </underlyingSecurity>
      <postTransactionAmounts>
        <sharesOwnedFollowingTransaction>
          <value>52500</value>
        </sharesOwnedFollowingTransaction>
      </postTransactionAmounts>
      <ownershipNature>
        <directOrIndirectOwnership>
          <value>D</value>
        </directOrIndirectOwnership>
      </ownershipNature>
    </derivativeTransaction>
  </derivativeTable>
  <footnotes>
    <footnote id="F1">Options for 12,500 shares shall vest monthly over one year commencing on September 4, 2003.</footnote>
  </footnotes>
  <ownerSignature>
    <signatureName>/s/ Paula S. Kasler, Attorney-in-Fact</signatureName>
    <signatureDate>2003-09-05</signatureDate>
  </ownerSignature>
</ownershipDocument>

</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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