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Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
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 TWSM7vrzLADbmYQaionwg5sDW3P6oaM5D3tdezXMm7z1T+B+twIDAQAB
MIC-Info: RSA-MD5,RSA,
 SUzoty08hG+09SJnpv/v0hAl6CfeE/DJboH6tzfMqhTgaAGxoHBcxI5vmcy4iMGA
 4V/dKz6LjcrhTVx1Cg1jWw==

<SEC-DOCUMENT>0001251384-06-000001.txt : 20060301
<SEC-HEADER>0001251384-06-000001.hdr.sgml : 20060301
<ACCEPTANCE-DATETIME>20060301171218
ACCESSION NUMBER:		0001251384-06-000001
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20060301
FILED AS OF DATE:		20060301
DATE AS OF CHANGE:		20060301

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			AMICAS, Inc.
		CENTRAL INDEX KEY:			0001028584
		STANDARD INDUSTRIAL CLASSIFICATION:	SERVICES-PREPACKAGED SOFTWARE [7372]
		IRS NUMBER:				592248411
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		20 GUEST STREET
		STREET 2:		SUITE 200
		CITY:			BOSTON
		STATE:			MA
		ZIP:			02135
		BUSINESS PHONE:		6177797878

	MAIL ADDRESS:	
		STREET 1:		20 GUEST STREET
		STREET 2:		SUITE 200
		CITY:			BOSTON
		STATE:			MA
		ZIP:			02135

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	VITALWORKS INC
		DATE OF NAME CHANGE:	20010809

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	VITAL WORKS INC
		DATE OF NAME CHANGE:	20010806

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	INFOCURE CORP
		DATE OF NAME CHANGE:	19961209

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			ZAPPALA LISA W
		CENTRAL INDEX KEY:			0001251384

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-25311
		FILM NUMBER:		06656673

	BUSINESS ADDRESS:	
		STREET 1:		ASPEN TECHNOLOGY INC
		STREET 2:		TEN CANAL PARK
		CITY:			CAMBRIDGE
		STATE:			MA
		ZIP:			02141
		BUSINESS PHONE:		617-779-7878

	MAIL ADDRESS:	
		STREET 1:		C/O AMICAS, INC.
		STREET 2:		20 GUEST STREET
		CITY:			BOSTON
		STATE:			MA
		ZIP:			02135
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>primary_doc.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0202</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2006-03-01</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001028584</issuerCik>
        <issuerName>AMICAS, Inc.</issuerName>
        <issuerTradingSymbol>amcs</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001251384</rptOwnerCik>
            <rptOwnerName>ZAPPALA LISA W</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O AMICAS, INC.</rptOwnerStreet1>
            <rptOwnerStreet2>20 GUEST STREET</rptOwnerStreet2>
            <rptOwnerCity>BOSTON</rptOwnerCity>
            <rptOwnerState>MA</rptOwnerState>
            <rptOwnerZipCode>02135</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Right to Buy</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>4.91</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2006-03-01</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>2500</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>4.91</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F1"/>
            </exerciseDate>
            <expirationDate>
                <value>2016-03-01</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>2500</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>2500</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">the stock options vest during a 24-month period, 50% on March 1, 2007 and 50% on March 1, 2008.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>Stephen Hicks for Lisa W. Zappala</signatureName>
        <signatureDate>2006-03-01</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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