<?xml version="1.0" encoding="utf-8"?>
<ownershipDocument>
    <schemaVersion>X0201</schemaVersion>

    <documentType>4</documentType>
  <periodOfReport>2003-12-02</periodOfReport>
  <notSubjectToSection16>0</notSubjectToSection16>
    <issuer>
        <issuerCik>0000884382</issuerCik>
        <issuerName>PRIMEDIA INC</issuerName>
        <issuerTradingSymbol>PRM</issuerTradingSymbol>
  </issuer>
  <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001235021</rptOwnerCik>
            <rptOwnerName>DISCEPOLO MICHAELANNE C</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O PRIMEDIA INC., 745 FIFTH AVE</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10151</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
            <reportingOwnerRelationship>
      <isDirector>0</isDirector>
      <isOfficer>1</isOfficer>
      <isTenPercentOwner>0</isTenPercentOwner>
      <isOther>0</isOther>
      <officerTitle>Executive VP,Human Resources</officerTitle>
    </reportingOwnerRelationship>
  </reportingOwner>
  <nonDerivativeTable>
    <nonDerivativeTransaction>
      <securityTitle>
        <value>Common Stock (Restricted)</value>
      </securityTitle>
      <transactionDate>
        <value>2003-12-02</value>
      </transactionDate>
      <transactionCoding>
        <transactionFormType>4</transactionFormType>
        <transactionCode>A</transactionCode>
        <equitySwapInvolved>0</equitySwapInvolved>
      </transactionCoding>
      <transactionTimeliness>
        <value></value>
      </transactionTimeliness>
      <transactionAmounts>
        <transactionShares>
          <value>200000</value>
        </transactionShares>
        <transactionPricePerShare>
          <footnoteId id="F1"/>
        </transactionPricePerShare>
        <transactionAcquiredDisposedCode>
          <value>A</value>
        </transactionAcquiredDisposedCode>
      </transactionAmounts>
      <postTransactionAmounts>
        <sharesOwnedFollowingTransaction>
          <value>202216</value>
          <footnoteId id="F2"/>
        </sharesOwnedFollowingTransaction>
      </postTransactionAmounts>
      <ownershipNature>
        <directOrIndirectOwnership>
          <value>D</value>
        </directOrIndirectOwnership>
      </ownershipNature>
    </nonDerivativeTransaction>
  </nonDerivativeTable>
  <footnotes>
    <footnote id="F1">Restricted Stock Grant; therefore there is no price</footnote>
    <footnote id="F2">Includes 716 shares of PRIMEDIA common stock under the PRIMEDIA 401(k) plan.</footnote>
  </footnotes>
  <ownerSignature>
    <signatureName>/s/ Michaelanne C. Discepolo</signatureName>
    <signatureDate>2003-12-04</signatureDate>
  </ownerSignature>
</ownershipDocument>

