BlackRock Insured Municipal Income Trust (BYM)

Schedule of Investments November 30, 2009 (Unaudited)

*

The cost and unrealized appreciation (depreciation) of investments as of November 30, 2009, as computed for federal income tax purposes, were as follows:

Aggregate cost

$

494,078,036

Gross unrealized appreciation

$

23,794,836

Gross unrealized depreciation

(28,604,688

)

Net unrealized depreciation

$

(4,809,852

)

(a)

Represents a zero-coupon bond. Rate shown reflects the current yield as of report date.

(b)

US government securities, held in escrow, are used to pay interest on this security as well as to retire the bond in full at the date indicated, typically at a premium to par.

(c)

Represents a step-up bond that pays an initial coupon rate for the first period and then a higher coupon rate for the following periods. Rate shown reflects the current yield as of report date.

(d)

Securities represent bonds transferred to tender option bond trust in exchange for which the Trust acquired residual interest certificates. These securities serve as collateral in a financing transaction.

(e)

Security may have a maturity of more than one year at time of issuance, but has variable rate and demand features that qualify it as a short-term security. Rate shown is as of report date and maturity shown is the date the principal owed can be recovered through demand.

(f)

Investments in companies considered to be an affiliate of the Trust, for purposes of Section 2(a)(3) of the Investment Company Act of 1940, were as follows:

Affiliate

Net
Activity

Income

FFI Institutional Tax-Exempt Fund

$

(3,101,744

)

$

936

(g)

Represents the current yield as of report date.

•

Fair Value Measurements - Various inputs are used in determining the fair value of investments, which are as follows:

•

Level 1 - price quotations in active markets/exchanges for identical assets and liabilities

•

Level 2 - other observable inputs (including, but not limited to: quoted prices for similar assets or liabilities in markets that are active, quoted prices for identical or similar assets or liabilities in markets that are not active, inputs other than quoted prices that are observable for the assets or liabilities (such as interest rates, yield curves, volatilities, prepayment speeds, loss severities, credit risks and default rates) or other market-corroborated inputs)

•

Level 3 - unobservable inputs based on the best information available in the circumstances, to the extent observable inputs are not available (including the Trust’s own assumptions used in determining the fair value of investments)

The inputs or methodology used for valuing securities are not necessarily an indication of the risk associated with investing in those securities. For information about the Trust’s policy regarding valuation of investments and other significant accounting policies, please refer to the Trust’s most recent financial statements as contained in its annual report.

The following table summarizes the inputs used as of November 30, 2009 in determining the fair valuation of the Trust’s investments:

Valuation
Inputs

Investments in
Securities

Assets

Level 1 - Short-Term Securities

$

1,300,000

Level 2:

Long-Term Investments¹

546,494,180

Short-Term Securities

2,700,000

Total Level 2

549,194,180

Level 3

—

Total

$

550,494,180

¹See above Schedule of Investments for values in each state or political subdivision.