    <SEC-DOCUMENT>0001193125-17-276450-index.html : 20170905
    <SEC-HEADER>0001193125-17-276450.hdr.sgml : 20170905
    <ACCEPTANCE-DATETIME>20170905125816
    ACCESSION NUMBER:		0001193125-17-276450
    CONFORMED SUBMISSION TYPE:	N-CSRS
    PUBLIC DOCUMENT COUNT:		17
    CONFORMED PERIOD OF REPORT:	20170630
    FILED AS OF DATE:		20170905
    DATE AS OF CHANGE:		20170905
    EFFECTIVENESS DATE:		20170905

    FILER:

    	COMPANY DATA:
    		COMPANY CONFORMED NAME:			BlackRock Utility & Infrastructure Trust
    		CENTRAL INDEX KEY:			0001528988
    		IRS NUMBER:				000000000
    		STATE OF INCORPORATION:			DE
    		FISCAL YEAR END:			1031

    	FILING VALUES:
    		FORM TYPE:		N-CSRS
    		SEC ACT:		1940 Act
    		SEC FILE NUMBER:	811-22606
    		FILM NUMBER:		171068070

    	BUSINESS ADDRESS:
    		STREET 1:		55 EAST 52ND STREET
    		CITY:			NEW YORK
    		STATE:			NY
    		ZIP:			10055
    		BUSINESS PHONE:		(800) 882-0052

    	MAIL ADDRESS:
    		STREET 1:		55 EAST 52ND STREET
    		CITY:			NEW YORK
    		STATE:			NY
    		ZIP:			10055
    </SEC-HEADER>
    <DOCUMENT>
    <TYPE>N-CSRS
    <SEQUENCE>1
    <FILENAME>d416307dncsrs.htm
    <DESCRIPTION>BLACKROCK UTILITY & INFRASTRUCTURE TRUST
    <TEXT>
    Document 1 - file: d416307dncsrs.htm

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>EX-99.CERT
    <SEQUENCE>2
    <FILENAME>d416307dex99cert.htm
    <DESCRIPTION>CERTIFICATION PURSUANT TO SECTION 302
    <TEXT>
    Document 2 - file: d416307dex99cert.htm

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>EX-99.906CERT
    <SEQUENCE>3
    <FILENAME>d416307dex99906cert.htm
    <DESCRIPTION>CERTIFICATION PURSUANT TO SECTION 906
    <TEXT>
    Document 3 - file: d416307dex99906cert.htm

    </DOCUMENT>
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    <TYPE>GRAPHIC
    <SEQUENCE>4
    <FILENAME>g407214photo_01mips.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 4 - file: g407214photo_01mips.jpg

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    <SEQUENCE>5
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    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 5 - file: g407214sig_01mips.jpg

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    <DESCRIPTION>GRAPHIC
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    Document 6 - file: g418959g03h14.jpg

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    <DESCRIPTION>GRAPHIC
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    Document 7 - file: g418959g14o44.jpg

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    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 8 - file: g418959g16t72.jpg

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    <SEQUENCE>9
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    <DESCRIPTION>GRAPHIC
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    Document 9 - file: g418959g21a05.jpg

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    <DESCRIPTION>GRAPHIC
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    Document 10 - file: g418959g56l23.jpg

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    <SEQUENCE>11
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    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 11 - file: g418959g57b79.jpg

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    <SEQUENCE>12
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    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 12 - file: g418959g65b16.jpg

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    <SEQUENCE>13
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    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 13 - file: g418959g81d05.jpg

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    <SEQUENCE>14
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    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 14 - file: g418959g82a35.jpg

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    <SEQUENCE>15
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    <DESCRIPTION>GRAPHIC
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    Document 15 - file: g418959g83f96.jpg

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    <DESCRIPTION>GRAPHIC
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    Document 16 - file: g418959g98u13.jpg

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    <SEQUENCE>17
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    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 17 - file: g418959leaf.jpg

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