Ownership Submission
FORM 3
 UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

INITIAL STATEMENT OF BENEFICIAL OWNERSHIP OF SECURITIES

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940
OMB APPROVAL
OMB Number: 3235-0104
Expires: January 31, 2005
Estimated average burden hours per response... 0.5

(Print or Type Responses)
1. Name and Address of Reporting Person *
  CITIGROUP INC
 2. Date of Event Requiring Statement (Month/Day/Year)
11/30/2008		 3. Issuer Name and Ticker or Trading Symbol
BLACKROCK INSURED MUNICIPAL INCOME TRUST [BYM]
(Last)
(First)
(Middle)
399 PARK AVENUE, 3RD FLOOR		 4. Relationship of Reporting Person(s) to Issuer
(Check all applicable)
_____ Director __X__ 10% Owner
_____ Officer (give title below) _____ Other (specify below)
5. If Amendment, Date Original Filed(Month/Day/Year)
(Street)

NEW YORK, NY 10043		 6. Individual or Joint/Group Filing(Check Applicable Line)
_X_ Form filed by One Reporting Person
___ Form filed by More than One Reporting Person
(City)
(State)
(Zip)
Table I - Non-Derivative Securities Beneficially Owned
1.Title of Security
(Instr. 4)		 2. Amount of Securities Beneficially Owned
(Instr. 4)		 3. Ownership Form: Direct (D) or Indirect (I)
(Instr. 5)		 4. Nature of Indirect Beneficial Ownership
(Instr. 5)
Auction Rate Preferred 1,900 (1)
I
By Subsidiary

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly. SEC 1473 (7-02)
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB control number.

Table II - Derivative Securities Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security
(Instr. 4)		 2. Date Exercisable and Expiration Date
(Month/Day/Year)		 3. Title and Amount of Securities Underlying Derivative Security
(Instr. 4)		 4. Conversion or Exercise Price of Derivative Security 5. Ownership Form of Derivative Security: Direct (D) or Indirect (I)
(Instr. 5)		 6. Nature of Indirect Beneficial Ownership
(Instr. 5)
Date Exercisable Expiration Date Title Amount or Number of Shares

Reporting Owners

Reporting Owner Name / Address Relationships
Director 10% Owner Officer Other
CITIGROUP INC
399 PARK AVENUE
3RD FLOOR
NEW YORK, NY 10043		     X    

Signatures

Citigroup Inc., By: /s/ Riqueza V. Feaster, Assistant Secretary 12/10/2008
**Signature of Reporting Person Date

Explanation of Responses:

* If the form is filed by more than one reporting person, see Instruction 5(b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations. See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
(1) The Auction Preferred Shares ("Shares") reported in Table I represent 1,900 Shares beneficially owned by Citigroup Global Markets Inc. ("CGMI"). Citigroup Financial Products Inc. ("CFP") is the sole stockholder of CGMI. Citigroup Global Markets Holdings Inc. ("CGMHI") is the sole stockholder of CFP. Citigroup Inc. ("Citigroup") is the sole stockholder of CGMHI.
 
Remarks:
The 1,900 Shares reported herein represent Citigroup's combined holdings in multiple series of auction preferred securities of the issuer, which are treated herein as one class of securities in accordance with the Auction Rate Securities -- Global Exemptive Relief no-action letter issued by the Securities and Exchange Commission (SEC) on September 22, 2008.  Citigroup undertakes to provide, upon request by the SEC staff, the issuer or a security holder of the issuer, complete information regarding the number of securities purchased or sold at each different price and date of all transactions in such securities that occurred after Citigroup became a 10% owner but prior to the date of this filing.

Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, See Instruction 6 for procedure.

Potential persons who are to respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB number.