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

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2019-05-20</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000101295</issuerCik>
        <issuerName>UNITED GUARDIAN INC</issuerName>
        <issuerTradingSymbol>UG</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0000943504</rptOwnerCik>
            <rptOwnerName>GLOBUS KENNETH H</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O UNITED-GUARDIAN, INC.</rptOwnerStreet1>
            <rptOwnerStreet2>230 MARCUS BLVD., P.O. BOX 18050</rptOwnerStreet2>
            <rptOwnerCity>HAUPPAUGE</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>11788</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>President</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2019-05-20</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>G</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>5600</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>1350853</value>
                    <footnoteId id="F1"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                    <footnoteId id="F1"/>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>295,426 shares owned by the wife; 760,000 shares as co-Trustee</value>
                    <footnoteId id="F1"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">After the transfer of the 5,600 shares being gifted, Reporting Person owns UG stock both directly and indirectly. Direct ownership is 295,427 shares, and Indirect ownership is 1,055,426 shares. Of the Indirect ownership, 295,426 shares are owned by the wife of the Reporting Person, and 760,000 shares are under the control of the Reporting Person in his role as co-Trustee of the Alfred R. Globus Testamentary Trust, the owner of those shares.</footnote>
    </footnotes>

    <remarks>In Box 6 Reporting Person indicated that his ownership was &quot;Indirect&quot;, but he has both Direct and Indirect ownership. There was no way to choose both Direct and Indirect ownership in this box, so this was explained and enumerated in Footnote #1.</remarks>

    <ownerSignature>
        <signatureName>/Ken Globus</signatureName>
        <signatureDate>2019-05-22</signatureDate>
    </ownerSignature>
</ownershipDocument>
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X0306
4
2019-05-20
0
0000101295
UNITED GUARDIAN INC
UG
0000943504
GLOBUS KENNETH H
C/O UNITED-GUARDIAN, INC.
230 MARCUS BLVD., P.O. BOX 18050
HAUPPAUGE
NY
11788
1
1
1
0
President
Common Stock
2019-05-20
4
G
0
5600
0
D
1350853
I
295,426 shares owned by the wife; 760,000 shares as co-Trustee
After the transfer of the 5,600 shares being gifted, Reporting Person owns UG stock both directly and indirectly. Direct ownership is 295,427 shares, and Indirect ownership is 1,055,426 shares. Of the Indirect ownership, 295,426 shares are owned by the wife of the Reporting Person, and 760,000 shares are under the control of the Reporting Person in his role as co-Trustee of the Alfred R. Globus Testamentary Trust, the owner of those shares.
In Box 6 Reporting Person indicated that his ownership was "Indirect", but he has both Direct and Indirect ownership. There was no way to choose both Direct and Indirect ownership in this box, so this was explained and enumerated in Footnote #1.
/Ken Globus
2019-05-22