-----BEGIN PRIVACY-ENHANCED MESSAGE-----
Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
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MIC-Info: RSA-MD5,RSA,
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 EN9a9ujUAHEOMKdX/gm34Q==

<SEC-DOCUMENT>0001251504-03-000003.txt : 20031002
<SEC-HEADER>0001251504-03-000003.hdr.sgml : 20031002
<ACCEPTANCE-DATETIME>20031002181452
ACCESSION NUMBER:		0001251504-03-000003
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20030925
FILED AS OF DATE:		20031002

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			PRO DEX INC
		CENTRAL INDEX KEY:			0000788920
		STANDARD INDUSTRIAL CLASSIFICATION:	WHOLESALE-MEDICAL, DENTAL & HOSPITAL EQUIPMENT & SUPPLIES [5047]
		IRS NUMBER:				841261240
		STATE OF INCORPORATION:			CO
		FISCAL YEAR END:			0630

	BUSINESS ADDRESS:	
		STREET 1:		650 S. TAYKOR AVENUE
		STREET 2:		SUITE 20-A
		CITY:			LOUISVILLE
		STATE:			CO
		ZIP:			80027
		BUSINESS PHONE:		3034438165

	MAIL ADDRESS:	
		STREET 1:		1401 WALNUT STREET
		STREET 2:		SUITE 540
		CITY:			BOULDER
		STATE:			CO
		ZIP:			80302

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			COSS RONALD G
		CENTRAL INDEX KEY:			0001251504

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-14942
		FILM NUMBER:		03925531

	BUSINESS ADDRESS:	
		STREET 1:		3 OVERLOOK DR.
		CITY:			NEWPORT COAST
		STATE:			CA
		ZIP:			92657
		BUSINESS PHONE:		9493767590

	MAIL ADDRESS:	
		STREET 1:		3 OVERLOOK DR
		CITY:			NEWPORT COAST
		STATE:			CA
		ZIP:			92657
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>primary_doc.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>

<ownershipDocument>

    <schemaVersion>X0201</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2003-09-25</periodOfReport>


    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000788920</issuerCik>
        <issuerName>PRO DEX INC</issuerName>
        <issuerTradingSymbol>pdex</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001251504</rptOwnerCik>
            <rptOwnerName>COSS RONALD G</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>3 OVERLOOK DR</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>NEWPORT COAST</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>92657</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>

        <nonDerivativeTransaction>
            <securityTitle>
                <value>Pro-Dex Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2003-09-25</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>12900</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>1.75</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>2273904</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                    <footnoteId id="F1"/>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>Trust</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>

        <nonDerivativeTransaction>
            <securityTitle>
                <value>Pro-Dex Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2003-09-25</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>1800</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>1.76</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>2272104</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>Trust</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>

    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">Indirect Ownership is in the form of a trust</footnote>
    </footnotes>


    <ownerSignature>
        <signatureName>Ronald G. Coss</signatureName>
        <signatureDate>2003-10-02</signatureDate>
    </ownerSignature>

</ownershipDocument>

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