UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM N-PX

ANNUAL REPORT OF PROXY VOTING RECORD OF REGISTERED

MANAGEMENT INVESTMENT COMPANY

Investment Company Act file number: 811-10333

Name of Fund: BlackRock Municipal Income Investment Trust (BBF)

Fund Address: 100 Bellevue Parkway, Wilmington, DE 19809

Name and address of agent for service: John Perlowski, Chief Executive Officer, BlackRock Municipal Income Investment Trust, 55 East 52^nd Street, New York City, NY 10055.

Registrant’s telephone number, including area code: (800) 882-0052, Option 4

Date of fiscal year end: 07/31

Date of reporting period: 07/01/2014 – 06/30/2015

Item 1 – Proxy Voting Record – There were no matters relating to a portfolio security considered at any shareholder meeting held during the period ended June 30, 2015 with respect to which the registrant was entitled to vote.

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ICA File Number: 811-10333
Reporting Period: 07/01/2014 - 06/30/2015
BlackRock Municipal Income Investment Trust









================= BlackRock Municipal Income Investment Trust ==================

There is no proxy voting activity for the fund, as the fund did not hold any
votable positions during the reporting period.
========== END NPX REPORT

Pursuant to the requirements of the Investment Company Act of 1940, the registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized.

BlackRock Municipal Income Investment Trust

Date: August 26, 2015