-----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,
 AbQwGHe8jKinxGcmH2X3ot54h39HcaBPmkrfXPqY1Zn8UBqOl0nPA9nQvWsJ7SiS
 pisWfRXr/vxIv6QQFq+qwA==

<SEC-DOCUMENT>0000940394-03-000949.txt : 20030814
<SEC-HEADER>0000940394-03-000949.hdr.sgml : 20030814
<ACCEPTANCE-DATETIME>20030814131544
ACCESSION NUMBER:		0000940394-03-000949
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20030812
FILED AS OF DATE:		20030814

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			EATON VANCE INSTITUTIONAL SENIOR FLOATING RATE FUND
		CENTRAL INDEX KEY:			0001080310
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		EATON VANCE INSTITUTIONAL
		STREET 2:		24 FEDERAL STREET
		CITY:			BOSTON
		STATE:			MA
		ZIP:			02110
		BUSINESS PHONE:		6174828260

	MAIL ADDRESS:	
		STREET 1:		EATON VANCE INSTITUTIONAL
		STREET 2:		24 FEDERAL STREET
		CITY:			BOSTON
		STATE:			MA
		ZIP:			02110

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			MCCDERMOTT CATHERINE C
		CENTRAL INDEX KEY:			0001225372

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	811-09249
		FILM NUMBER:		03845480

	BUSINESS ADDRESS:	
		STREET 1:		255 STATE STREET
		CITY:			BOSTON
		STATE:			MA
		ZIP:			02109
		BUSINESS PHONE:		6174828260

	MAIL ADDRESS:	
		STREET 1:		255 STATE STREET
		CITY:			BOSTON
		STATE:			MA
		ZIP:			02109
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>mcd5.xml
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>
    <schemaVersion>X0201</schemaVersion>

    <documentType>4</documentType>
	<periodOfReport>2003-08-12</periodOfReport>
	<notSubjectToSection16>1</notSubjectToSection16>
    <issuer>
        <issuerCik>0001080310</issuerCik>
        <issuerName>EATON VANCE INSTITUTIONAL SENIOR FLOATING RATE FUND</issuerName>
        <issuerTradingSymbol>EIFRX</issuerTradingSymbol>
	</issuer>
	<reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001225372</rptOwnerCik>
            <rptOwnerName>MCCDERMOTT CATHERINE C</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>THE EATON VANCE BUILDING</rptOwnerStreet1>
            <rptOwnerStreet2>255 STATE STREET</rptOwnerStreet2>
            <rptOwnerCity>BOSTON</rptOwnerCity>
            <rptOwnerState>MA</rptOwnerState>
            <rptOwnerZipCode>02109</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
            <reportingOwnerRelationship>
			<isDirector>0</isDirector>
			<isOfficer>0</isOfficer>
			<isTenPercentOwner>0</isTenPercentOwner>
			<isOther>1</isOther>
			<otherText>Insider and Officer</otherText>
		</reportingOwnerRelationship>
	</reportingOwner>
	<footnotes>
	</footnotes>
	<remarks>
	</remarks>
	<ownerSignature>
		<signatureName>By: Paul M. O'Neil, Attorney in Fact</signatureName>
		<signatureDate>2003-08-14</signatureDate>
	</ownerSignature>
</ownershipDocument>

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