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

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2018-09-24</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>2018-09-24</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>G</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>5620</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>1362053</value>
                    <footnoteId id="F1"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                    <footnoteId id="F1"/>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>301,026 shares held by wife; 760,000 shares as trustee</value>
                    <footnoteId id="F1"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">After the transfer of the 5,620 shares being gifted, Reporting Person's Direct ownership is 301,027 shares, and Indirect ownership is 1,061,026 shares. Of the Indirect ownership, 301,026 share are owned by the wife of the Reporting Person, and 760,000 shares are under the direct control of the Reporting Person as co-trustee of the Alfred R. Globus Testamentary Trust.</footnote>
    </footnotes>

    <remarks>Since this form doesn't allow detailed explanations if &quot;Direct&quot; ownership&quot; is indicated in box 10, Reporting Person has used &quot;Indirect&quot; in box 10 so that a more detailed explanation of Reporting Person's ownership can be described. As a result, there are 301,027 shares that are owned Directly by Reporting Person, and the balance of the 1,362,053 shares are beneficially owned by Reporting person due to the ownership of 301,026 shares by Reporting Person's wife, and 760,000 shares owned by the Alfred R. Globus Testamentary Trust, of which the Reporting Person is a co-trustee.</remarks>

    <ownerSignature>
        <signatureName>/s/ Ken Globus</signatureName>
        <signatureDate>2018-09-25</signatureDate>
    </ownerSignature>
</ownershipDocument>
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X0306
4
2018-09-24
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
2018-09-24
4
G
0
5620
0
D
1362053
I
301,026 shares held by wife; 760,000 shares as trustee
After the transfer of the 5,620 shares being gifted, Reporting Person's Direct ownership is 301,027 shares, and Indirect ownership is 1,061,026 shares. Of the Indirect ownership, 301,026 share are owned by the wife of the Reporting Person, and 760,000 shares are under the direct control of the Reporting Person as co-trustee of the Alfred R. Globus Testamentary Trust.
Since this form doesn't allow detailed explanations if "Direct" ownership" is indicated in box 10, Reporting Person has used "Indirect" in box 10 so that a more detailed explanation of Reporting Person's ownership can be described. As a result, there are 301,027 shares that are owned Directly by Reporting Person, and the balance of the 1,362,053 shares are beneficially owned by Reporting person due to the ownership of 301,026 shares by Reporting Person's wife, and 760,000 shares owned by the Alfred R. Globus Testamentary Trust, of which the Reporting Person is a co-trustee.
/s/ Ken Globus
2018-09-25