-----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,
 MqHknIWW+rn/ul1PrnKWvTg0ezvnmTY9SU0MAsWZWuY+0fKp+EFgvMvkg29rZuS4
 AaIRpbX1fyRBa3A+bvDwzg==

<SEC-DOCUMENT>0001253828-05-000002.txt : 20050611
<SEC-HEADER>0001253828-05-000002.hdr.sgml : 20050611
<ACCEPTANCE-DATETIME>20050525090114
ACCESSION NUMBER:		0001253828-05-000002
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20050524
FILED AS OF DATE:		20050525
DATE AS OF CHANGE:		20050525

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			PLC SYSTEMS INC
		CENTRAL INDEX KEY:			0000879682
		STANDARD INDUSTRIAL CLASSIFICATION:	ELECTROMEDICAL & ELECTROTHERAPEUTIC APPARATUS [3845]
		IRS NUMBER:				043153858
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		10 FORGE PK
		CITY:			FRANKLIN
		STATE:			MA
		ZIP:			02038
		BUSINESS PHONE:		5085418800

	MAIL ADDRESS:	
		STREET 1:		10 FORGE PARK
		CITY:			FRANKLIN
		STATE:			MA
		ZIP:			02038

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			ADAMS MICHAEL F
		CENTRAL INDEX KEY:			0001253828

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-11388
		FILM NUMBER:		05855572

	MAIL ADDRESS:	
		STREET 1:		78 E OLYMPIA AVE
		STREET 2:		C/O CARDIO TECH INTERNATIONAL INC
		CITY:			WOBURN
		STATE:			MA
		ZIP:			01810-2057
</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>2005-05-24</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000879682</issuerCik>
        <issuerName>PLC SYSTEMS INC</issuerName>
        <issuerTradingSymbol>PLC</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001253828</rptOwnerCik>
            <rptOwnerName>ADAMS MICHAEL F</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>PLC MEDICAL SYSTEMS, INC.</rptOwnerStreet1>
            <rptOwnerStreet2>10 FORGE PARK</rptOwnerStreet2>
            <rptOwnerCity>FRANKLIN</rptOwnerCity>
            <rptOwnerState>MA</rptOwnerState>
            <rptOwnerZipCode>02038</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>VP, New Ventures and QA/RA</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Common Stock (Right to Buy)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>0.55</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2005-05-24</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>72727</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0.55</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <value>2005-05-24</value>
                <footnoteId id="F1"/>
            </exerciseDate>
            <expirationDate>
                <value>2015-05-23</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>72727</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>72727</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">This option is currently exercisable with respect to the 72,727 shares of Common Stock.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>Michael F. Adams</signatureName>
        <signatureDate>2005-05-25</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
-----END PRIVACY-ENHANCED MESSAGE-----