<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0202</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2005-08-17</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001022505</issuerCik>
        <issuerName>NATIONAL SCIENTIFIC CORP/AZ</issuerName>
        <issuerTradingSymbol>NSCT.OB</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001129846</rptOwnerCik>
            <rptOwnerName>GROLLMAN MICHAEL A</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>14505 N. HAYDEN ROAD, SUITE 305</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>SCOTTSDALE</rptOwnerCity>
            <rptOwnerState>AZ</rptOwnerState>
            <rptOwnerZipCode>85260</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>CEO; Chairman</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>NSCT Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2005-08-17</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>J</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>750000</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0.046</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>3766000</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">These restricted shares are acquired as partial collateral against current debt obligations owed to Mr. Grollman, as discussed in the Company's SEC filings, including its 10-KSB report for the fiscal year ending September 30, 2004, and its 10-QSB reports for the current fiscal year, including for the period ending June 30, 2005.  These share issuances are subject to substantial risk of forfeiture should the Company pay its debt obligations in full and promptly, prior to any formal demand for full payment by Mr. Grollman.  In the event of nonpayment and such a demand, these restricted shares are the property of Mr. Grollman.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ Michael A. Grollman</signatureName>
        <signatureDate>2005-08-17</signatureDate>
    </ownerSignature>
</ownershipDocument>
