-----BEGIN PRIVACY-ENHANCED MESSAGE-----
Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
Originator-Key-Asymmetric:
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 TWSM7vrzLADbmYQaionwg5sDW3P6oaM5D3tdezXMm7z1T+B+twIDAQAB
MIC-Info: RSA-MD5,RSA,
 MAFIJD6IbdeSlMvx82WMWqDBVCrbsuY/VuqZhceNtwrhw2Bv3rykd6EdcoYcwQ7z
 epa9sJO6Q9p1er4dL4f2uA==

<SEC-DOCUMENT>0001106372-08-000048.txt : 20080401
<SEC-HEADER>0001106372-08-000048.hdr.sgml : 20080401
<ACCEPTANCE-DATETIME>20080401123757
ACCESSION NUMBER:		0001106372-08-000048
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20080331
FILED AS OF DATE:		20080401
DATE AS OF CHANGE:		20080401

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			RF MONOLITHICS INC /DE/
		CENTRAL INDEX KEY:			0000922204
		STANDARD INDUSTRIAL CLASSIFICATION:	RADIO & TV BROADCASTING & COMMUNICATIONS EQUIPMENT [3663]
		IRS NUMBER:				751638027
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			0831

	BUSINESS ADDRESS:	
		STREET 1:		4347 SIGMA RD
		CITY:			DALLAS
		STATE:			TX
		ZIP:			75244
		BUSINESS PHONE:		9722332903

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			CAMPBELL DEAN C
		CENTRAL INDEX KEY:			0001142444

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-24414
		FILM NUMBER:		08728256

	BUSINESS ADDRESS:	
		STREET 1:		4347 SIGMA RD
		CITY:			DALLAS
		STATE:			TX
		ZIP:			75224
		BUSINESS PHONE:		972.233.2903

	MAIL ADDRESS:	
		STREET 1:		C/O RF MONOLITHICS, INC.
		STREET 2:		4441 SIGMA ROAD
		CITY:			DALLAS
		STATE:			TX
		ZIP:			75244
</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>2008-03-31</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000922204</issuerCik>
        <issuerName>RF MONOLITHICS INC /DE/</issuerName>
        <issuerTradingSymbol>rfmi</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001142444</rptOwnerCik>
            <rptOwnerName>CAMPBELL DEAN C</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O RF MONOLITHICS, INC.</rptOwnerStreet1>
            <rptOwnerStreet2>4441 SIGMA ROAD</rptOwnerStreet2>
            <rptOwnerCity>DALLAS</rptOwnerCity>
            <rptOwnerState>TX</rptOwnerState>
            <rptOwnerZipCode>75244</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>2008-03-31</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>4750</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>2.39</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>44750</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By IRA</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <ownerSignature>
        <signatureName>Curtis G. Carlson, as Attorney-in-Fact</signatureName>
        <signatureDate>2008-04-01</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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