-----BEGIN PRIVACY-ENHANCED MESSAGE-----
Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
Originator-Key-Asymmetric:
 MFgwCgYEVQgBAQICAf8DSgAwRwJAW2sNKK9AVtBzYZmr6aGjlWyK3XmZv3dTINen
 TWSM7vrzLADbmYQaionwg5sDW3P6oaM5D3tdezXMm7z1T+B+twIDAQAB
MIC-Info: RSA-MD5,RSA,
 BGKgf30vjW80BZn2oYRwyy42w66ZDXDpRI67hvJRLO/Qz8o25ZFW3dqqwhk5nm3D
 PIn3h99xOxh+fkPNg31DAg==

<SEC-DOCUMENT>0001179110-04-011134.txt : 20040521
<SEC-HEADER>0001179110-04-011134.hdr.sgml : 20040521
<ACCEPTANCE-DATETIME>20040521114423
ACCESSION NUMBER:		0001179110-04-011134
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20040520
FILED AS OF DATE:		20040521

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			YOUNG DALE L
		CENTRAL INDEX KEY:			0001202014

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-14429
		FILM NUMBER:		04823187

	BUSINESS ADDRESS:	
		STREET 1:		4700 SUPERIOR STREET
		CITY:			LINCOLN
		STATE:			NE
		ZIP:			68504
		BUSINESS PHONE:		4024640231

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			ISCO INC
		CENTRAL INDEX KEY:			0000773730
		STANDARD INDUSTRIAL CLASSIFICATION:	INDUSTRIAL INSTRUMENTS FOR MEASUREMENT, DISPLAY, AND CONTROL [3823]
		IRS NUMBER:				470461807
		STATE OF INCORPORATION:			NE
		FISCAL YEAR END:			0730

	BUSINESS ADDRESS:	
		STREET 1:		4700 SUPERIOR ST
		CITY:			LINCOLN
		STATE:			NE
		ZIP:			68504
		BUSINESS PHONE:		4024640231

	MAIL ADDRESS:	
		STREET 1:		4700 SUPERIOR ST
		CITY:			LINCOLN
		STATE:			NE
		ZIP:			68504
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>edgar.xml
<DESCRIPTION>FORM 4 -
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0202</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2004-05-20</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000773730</issuerCik>
        <issuerName>ISCO INC</issuerName>
        <issuerTradingSymbol>ISKO</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001202014</rptOwnerCik>
            <rptOwnerName>YOUNG DALE L</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>P.O. 82531</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>LINCOLN</rptOwnerCity>
            <rptOwnerState>NE</rptOwnerState>
            <rptOwnerZipCode>68531</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Isco Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2004-05-20</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>G</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>1696</value>
                </transactionShares>
                <transactionPricePerShare>
                    <footnoteId id="F1"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>24126</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Isco Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>1988-08-08</value>
                <footnoteId id="F2"/>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>0</value>
                    <footnoteId id="F2"/>
                </transactionShares>
                <transactionPricePerShare>
                    <footnoteId id="F2"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>7000</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>Trust</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">Mr. Young donated 1,696 shares of Isco Common Stock.</footnote>
        <footnote id="F2">No transaction to report simply listing Mr. Young's indirect ownership.</footnote>
    </footnotes>

    <remarks>This Form 4 Filing is the result of a gift by Mr. Young prior to calendar year 2002 which incorrectly was not reported as required.</remarks>

    <ownerSignature>
        <signatureName>Dale L. Young</signatureName>
        <signatureDate>2004-05-21</signatureDate>
    </ownerSignature>
</ownershipDocument>

</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
-----END PRIVACY-ENHANCED MESSAGE-----