-----BEGIN PRIVACY-ENHANCED MESSAGE-----
Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
Originator-Key-Asymmetric:
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MIC-Info: RSA-MD5,RSA,
 CcnQ6zWwEYEtoOIEefQaFOkU0+lfyO6pVllzB8opfnaQhlsb25/L15XloUa8ouAs
 URtUrYYx94IHDhC68f1c9w==

<SEC-DOCUMENT>0000024751-10-000086.txt : 20100707
<SEC-HEADER>0000024751-10-000086.hdr.sgml : 20100707
<ACCEPTANCE-DATETIME>20100707091850
ACCESSION NUMBER:		0000024751-10-000086
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20100706
FILED AS OF DATE:		20100707
DATE AS OF CHANGE:		20100707

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Smith Thomas Joseph
		CENTRAL INDEX KEY:			0001204316

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-00643
		FILM NUMBER:		10941033

	MAIL ADDRESS:	
		STREET 1:		8500 STATION STREET SUITE 100
		CITY:			MENTOR
		STATE:			OH
		ZIP:			44060

	FORMER NAME:	
		FORMER CONFORMED NAME:	SMITH THOMAS JAMES
		DATE OF NAME CHANGE:	20021107

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			CORNING NATURAL GAS CORP
		CENTRAL INDEX KEY:			0000024751
		STANDARD INDUSTRIAL CLASSIFICATION:	NATURAL GAS TRANSMISSION & DISTRIBUTION [4923]
		IRS NUMBER:				160397420
		STATE OF INCORPORATION:			NY
		FISCAL YEAR END:			0930

	BUSINESS ADDRESS:	
		STREET 1:		330 W WILLIAM ST
		STREET 2:		P O BOX 58
		CITY:			CORNING
		STATE:			NY
		ZIP:			14830
		BUSINESS PHONE:		6079363755

	MAIL ADDRESS:	
		STREET 1:		330 W WILLIAM STREET
		STREET 2:		P O BOX 58
		CITY:			CORNING
		STATE:			NY
		ZIP:			14830
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>primary_doc.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0303</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2010-07-06</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000024751</issuerCik>
        <issuerName>CORNING NATURAL GAS CORP</issuerName>
        <issuerTradingSymbol>cnig</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001204316</rptOwnerCik>
            <rptOwnerName>Smith Thomas Joseph</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>8500 STATION STREET SUITE 100</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>MENTOR</rptOwnerCity>
            <rptOwnerState>OH</rptOwnerState>
            <rptOwnerZipCode>44060</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2010-07-06</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>250</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>20</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>1550</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <ownerSignature>
        <signatureName>George J Welch Attorney-in-fact for Thomas Joseph Smith</signatureName>
        <signatureDate>2010-07-07</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
-----END PRIVACY-ENHANCED MESSAGE-----