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

    <schemaVersion>X0202</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2007-12-04</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000008328</issuerCik>
        <issuerName>ATLAS MINING CO</issuerName>
        <issuerTradingSymbol>ALMIE</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001414860</rptOwnerCik>
            <rptOwnerName>IBS CAPITAL LLC</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>ONE INTERNATIONAL PLACE</rptOwnerStreet1>
            <rptOwnerStreet2>SUITE 2401</rptOwnerStreet2>
            <rptOwnerCity>BOSTON</rptOwnerCity>
            <rptOwnerState>MA</rptOwnerState>
            <rptOwnerZipCode>02110</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001415021</rptOwnerCik>
            <rptOwnerName>IBS TURNAROUND FUND (QP) (A LTD PARTNERSHIP)</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>ONE INTERNATIONAL PLACE</rptOwnerStreet1>
            <rptOwnerStreet2>STE 2410</rptOwnerStreet2>
            <rptOwnerCity>BOSTON</rptOwnerCity>
            <rptOwnerState>MA</rptOwnerState>
            <rptOwnerZipCode>02110</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2007-12-04</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>262500</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0.5987</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>9689082</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See Note 1.</value>
                    <footnoteId id="F1"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">IBS Capital LLC is the general partner of (i) The IBS Turnaround (QP) Fund (A Limited Partnership), which holds 6,263,991 shares, and (ii) The IBS Turnaround Fund (A Limited Partnership), which holds 2,124,816 shares.  IBS Capital LLC is the Investment Manager of The IBS Opportunity Fund (BVI), Ltd., which holds 1,300,275 shares.  The 262,500 shares purchased on December 4, 2007 were purchased as follows: (i) 175,220 shares were purchased by The IBS Turnaround (QP) Fund (A Limited Partnership); (ii) 57,654 shares were purchased by the The IBS Turnaround Fund (A Limited Partnership); and (iii) 29,626 shares were purchased by The IBS Opportunity Fund (BVI), Ltd.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>IBS Capital LLC, by David A. Taft, Manager</signatureName>
        <signatureDate>2007-12-06</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>IBS TURNAROUND FUND (QP) (A LTD PARTNERSHIP) By IBS Capital LLC, Its General Partner, David A. Taft, Manager</signatureName>
        <signatureDate>2007-12-06</signatureDate>
    </ownerSignature>
</ownershipDocument>
