<SUBMISSION>
<ACCESSION-NUMBER>0000933430-03-000004
<TYPE>4
<PUBLIC-DOCUMENT-COUNT>1
<PERIOD>20030908
<FILING-DATE>20030910
<ISSUER>
<COMPANY-DATA>
<CONFORMED-NAME>NANOPHASE TECHNOLOGIES CORPORATION
<CIK>0000883107
<ASSIGNED-SIC>3390
<IRS-NUMBER>363687863
<STATE-OF-INCORPORATION>IL
<FISCAL-YEAR-END>1231
</COMPANY-DATA>
<BUSINESS-ADDRESS>
<STREET1>453 COMMERCE ST
<CITY>BURR RIDGE
<STATE>IL
<ZIP>60521
<PHONE>6303231200
</BUSINESS-ADDRESS>
<MAIL-ADDRESS>
<STREET1>453 COMMERCE STREET
<CITY>BURR RIDGE
<STATE>IL
<ZIP>60521
</MAIL-ADDRESS>
</ISSUER>
<REPORTING-OWNER>
<OWNER-DATA>
<CONFORMED-NAME>WHITMORE BRADFORD T
<CIK>0000933430
<STATE-OF-INCORPORATION>IL
<FISCAL-YEAR-END>1231
</OWNER-DATA>
<FILING-VALUES>
<FORM-TYPE>4
<ACT>34
<FILE-NUMBER>000-22333
<FILM-NUMBER>03890563
</FILING-VALUES>
<BUSINESS-ADDRESS>
<STREET1>1560 SHERMAN AVE
<STREET2>SUITE 900
<CITY>EVANSTON
<STATE>IL
<ZIP>60201
<PHONE>8477331230
</BUSINESS-ADDRESS>
<MAIL-ADDRESS>
<STREET1>1560 SHERMAN AVE
<STREET2>SUITE 900
<CITY>EVANSTON
<STATE>IL
<ZIP>60201
</MAIL-ADDRESS>
</REPORTING-OWNER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>primary_doc.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>

<ownershipDocument>

    <schemaVersion>X0201</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2003-09-08</periodOfReport>


    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000883107</issuerCik>
        <issuerName>NANOPHASE TECHNOLOGIES CORPORATION</issuerName>
        <issuerTradingSymbol>NANX</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0000933430</rptOwnerCik>
            <rptOwnerName>WHITMORE BRADFORD T</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>1560 SHERMAN AVE</rptOwnerStreet1>
            <rptOwnerStreet2>SUITE 900</rptOwnerStreet2>
            <rptOwnerCity>EVANSTON</rptOwnerCity>
            <rptOwnerState>IL</rptOwnerState>
            <rptOwnerZipCode>60201</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>

        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2003-09-08</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>453001</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>4.415</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>3601944</value>
                    <footnoteId id="F2"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>*</value>
                    <footnoteId id="F1"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>

    </nonDerivativeTable>

    <derivativeTable>

        <derivativeTransaction>
            <securityTitle>
                <value>Stock Option</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>4.415</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2003-09-08</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>453001</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>4.415</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <value>2003-09-08</value>
            </exerciseDate>
            <expirationDate>
                <value>2004-09-08</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>453001</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>453001</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>*</value>
                    <footnoteId id="F1"/>
                </natureOfOwnership>
            </ownershipNature>
        </derivativeTransaction>

    </derivativeTable>

    <footnotes>
        <footnote id="F1">*As General Partner of Grace Brothers, Ltd. which owns 2,532,194 and as General Partner of Grace Investments, Ltd. which owns 1,069,750 shares.</footnote>
        <footnote id="F2">*Bradford T. Whitmore directly owns 472,812 shares.</footnote>
    </footnotes>


    <ownerSignature>
        <signatureName>Bradford T. Whitmore</signatureName>
        <signatureDate>2003-09-10</signatureDate>
    </ownerSignature>

</ownershipDocument>

</XML>
</TEXT>
</DOCUMENT>
</SUBMISSION>
