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Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
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MIC-Info: RSA-MD5,RSA,
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<SEC-DOCUMENT>0001179110-06-000141.txt : 20060104
<SEC-HEADER>0001179110-06-000141.hdr.sgml : 20060104
<ACCEPTANCE-DATETIME>20060104104824
ACCESSION NUMBER:		0001179110-06-000141
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20051231
FILED AS OF DATE:		20060104
DATE AS OF CHANGE:		20060104

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			DUFFY SEAN P
		CENTRAL INDEX KEY:			0001225718

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-23211
		FILM NUMBER:		06504953

	BUSINESS ADDRESS:	
		STREET 1:		25 GREENS HILL LANE
		STREET 2:		PO BOX 866
		CITY:			RUTLAND
		STATE:			VT
		ZIP:			06702
		BUSINESS PHONE:		802 775 0325

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			CASELLA WASTE SYSTEMS INC
		CENTRAL INDEX KEY:			0000911177
		STANDARD INDUSTRIAL CLASSIFICATION:	REFUSE SYSTEMS [4953]
		IRS NUMBER:				030338873
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			0430

	BUSINESS ADDRESS:	
		STREET 1:		25 GREENS HILL LANE P O BOX 866
		CITY:			RUTLAND
		STATE:			VT
		ZIP:			05701
		BUSINESS PHONE:		8027750325

	MAIL ADDRESS:	
		STREET 1:		25 GREENE HILL ROAD
		CITY:			RUTLAND
		STATE:			VT
		ZIP:			05702
</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>2005-12-31</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000911177</issuerCik>
        <issuerName>CASELLA WASTE SYSTEMS INC</issuerName>
        <issuerTradingSymbol>CWST</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001225718</rptOwnerCik>
            <rptOwnerName>DUFFY SEAN P</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O CASELLA WASTE SYSTEMS, INC.</rptOwnerStreet1>
            <rptOwnerStreet2>25 GREENS HILL LANE</rptOwnerStreet2>
            <rptOwnerCity>RUTLAND</rptOwnerCity>
            <rptOwnerState>VT</rptOwnerState>
            <rptOwnerZipCode>05701</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Regional Vice President</officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Class A Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2005-12-31</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>J</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F1"/>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>188</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>10.4975</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>65907</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">Shares were acquired pursuant to the Casella Waste Systems, Inc. Amended and Restated 1997 Employee Stock Purchase Plan.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ Sean P. Duffy</signatureName>
        <signatureDate>2006-01-04</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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