    <SEC-DOCUMENT>0001193125-25-230077-index.html : 20251003
    <SEC-HEADER>0001193125-25-230077.hdr.sgml : 20251003
    <ACCEPTANCE-DATETIME>20251003160347
    ACCESSION NUMBER:		0001193125-25-230077
    CONFORMED SUBMISSION TYPE:	N-CSR
    PUBLIC DOCUMENT COUNT:		17
    CONFORMED PERIOD OF REPORT:	20250731
    FILED AS OF DATE:		20251003
    DATE AS OF CHANGE:		20251003
    EFFECTIVENESS DATE:		20251003

    FILER:

    	COMPANY DATA:
    		COMPANY CONFORMED NAME:			BLACKROCK MUNIVEST FUND II, INC.
    		CENTRAL INDEX KEY:			0000897269
    		ORGANIZATION NAME:
    		EIN:				223220659
    		STATE OF INCORPORATION:			MD
    		FISCAL YEAR END:			1031

    	FILING VALUES:
    		FORM TYPE:		N-CSR
    		SEC ACT:		1940 Act
    		SEC FILE NUMBER:	811-07478
    		FILM NUMBER:		251373689

    	BUSINESS ADDRESS:
    		STREET 1:		100 BELLEVUE PARKWAY
    		CITY:			WILMINGTON
    		STATE:			DE
    		ZIP:			19809
    		BUSINESS PHONE:		800-441-7762

    	MAIL ADDRESS:
    		STREET 1:		100 BELLEVUE PARKWAY
    		CITY:			WILMINGTON
    		STATE:			DE
    		ZIP:			19809

    	FORMER COMPANY:
    		FORMER CONFORMED NAME:	BLACKROCK MUNIVEST FUND II INC
    		DATE OF NAME CHANGE:	20061026

    	FORMER COMPANY:
    		FORMER CONFORMED NAME:	MUNIVEST FUND II INC
    		DATE OF NAME CHANGE:	19930714
    </SEC-HEADER>
    <DOCUMENT>
    <TYPE>N-CSR
    <SEQUENCE>1
    <FILENAME>d927219dncsr.htm
    <DESCRIPTION>BLACKROCK MUNIVEST FUND II, INC.
    <TEXT>
    Document 1 - file: d927219dncsr.htm

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>EX-99.CERT
    <SEQUENCE>2
    <FILENAME>d927219dex99cert.htm
    <DESCRIPTION>CERTIFICATION PURSUANT TO SECTION 302
    <TEXT>
    Document 2 - file: d927219dex99cert.htm

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>EX-99.906CERT
    <SEQUENCE>3
    <FILENAME>d927219dex99906cert.htm
    <DESCRIPTION>CERTIFICATION PURSUANT TO SECTION 906
    <TEXT>
    Document 3 - file: d927219dex99906cert.htm

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>EX-99.PROXYPOL
    <SEQUENCE>4
    <FILENAME>d927219dex99proxypol.htm
    <DESCRIPTION>PROXY VOTING POLICY AND PROCEDURES
    <TEXT>
    Document 4 - file: d927219dex99proxypol.htm

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    <TYPE>GRAPHIC
    <SEQUENCE>5
    <FILENAME>g927219dsp15.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 5 - file: g927219dsp15.jpg

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    <TYPE>GRAPHIC
    <SEQUENCE>6
    <FILENAME>g927219dsp15a.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 6 - file: g927219dsp15a.jpg

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    <SEQUENCE>7
    <FILENAME>g927219g99t17.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 7 - file: g927219g99t17.jpg

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    <SEQUENCE>8
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    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 8 - file: g927219img0f86c9dc6.gif

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    <SEQUENCE>9
    <FILENAME>g927219img2b1fce842.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 9 - file: g927219img2b1fce842.jpg

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    <SEQUENCE>10
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    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 10 - file: g927219img5f7d34f58.gif

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    <TYPE>GRAPHIC
    <SEQUENCE>11
    <FILENAME>g927219img67aeae2b10.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 11 - file: g927219img67aeae2b10.jpg

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    <TYPE>GRAPHIC
    <SEQUENCE>12
    <FILENAME>g927219img807c9c2e1.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 12 - file: g927219img807c9c2e1.jpg

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    <SEQUENCE>13
    <FILENAME>g927219img995db7a79.gif
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 13 - file: g927219img995db7a79.gif

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    <TYPE>GRAPHIC
    <SEQUENCE>14
    <FILENAME>g927219imga1463e024.gif
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 14 - file: g927219imga1463e024.gif

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    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>15
    <FILENAME>g927219imga98e299d3.gif
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 15 - file: g927219imga98e299d3.gif

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    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>16
    <FILENAME>g927219imgbef85fd57.gif
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 16 - file: g927219imgbef85fd57.gif

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    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>17
    <FILENAME>g927219imgc72dd0175.gif
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 17 - file: g927219imgc72dd0175.gif

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