Western Asset Mortgage Defined Opportunity Fund Inc. as of December 31, 2010

NEW YORK--([ BUSINESS WIRE ])--Western Asset Mortgage Defined Opportunity Fund Inc. (NYSE: DMO) announces its portfolio composition as of December 31, 2010.

Investment Objectives: The Funda�s primary investment objective is to provide current income. As a secondary investment objective, the Fund will seek capital appreciation.

Investment Strategy: The Fund seeks to achieve its investment objectives by investing primarily in a diverse portfolio of mortgage-backed securities (aMBSa) consisting primarily of non-agency residential mortgage-backed securities ("RMBS") and commercial mortgage-backed securities ("CMBS"). The Fund intends to invest in MBS directly, and indirectly through a separate investment in a public-private investment fund ("PPIF") formed in connection with the Legacy Securities Public-Private Investment Program ("PPIP") established by the U.S. Department of the Treasury.

Portfolio Composition*:

Asset Allocation
RMBS				93.9%
Prime				34.8%
Alt-A				33.2%
Option ARM				13.0%
Sub-prime				12.9%
CMBS				2.4%
Asset-Backed				2.0%
Cash & Cash Equivalents				1.8%

Credit Quality Allocation**
AAA				3.4%
AA				3.5%
A				13.6%
BBB				12.0%
BB				7.5%
B				8.5%
CCC				1.1%
CC				12.2%
C				35.2%
D				1.8%
Not Rated				1.2%

Average Life (years)				4.9
Effective Duration (years)				1.4
Average Coupon (%)				3.3

Portfolio Statistics:

Inception Date	February 24, 2010
Inception Price	$20.00
Total Assets***	$272,016,837
Net Assets	$227,834,194
Loans		0.00%
Preferred Shares		0.00%
Reverse Repos		16.24%

Market Price	$21.60
NAV	$21.98

(Daily NAV is available on market quotation systems using the symbol XDMOX.)

Distribution Rate				$0.1400 per share
Frequency				Monthly (Declared quarterly, paid monthly)

*		The Fund has also invested in a PPIF. The data (except for aTotal Assetsa, aNet Assetsa and the sub-headings thereunder) included in this press release incorporates the Fund's pro rata exposure to the PPIFa�s holdings. Portfolio holdings and weightings are historical and are presented here for informational purposes only. They are subject to change at any time.
**		Credit quality is a measure of a bond issuer's ability to repay interest and principal in a timely manner. The credit ratings shown are based on each portfolio security's rating as provided by Standard and Poor's, Moody's Investors Service and/or Fitch Ratings, Ltd. For this purpose, if two or more of the agencies have assigned differing ratings to a security, the highest rating is used. Securities that are unrated by all three agencies are reflected as such. The credit quality of the investments in the Fund's portfolio does not apply to the stability or safety of the Fund. These ratings are updated monthly and may change over time. Please note, the Fund itself has not been rated by an independent rating agency.
***		The difference between total assets and net assets, if any, is due primarily to the Funda�s use of borrowings; net assets do not include borrowings. The Fund may employ leverage in the form of loans, preferred stock, reverse repurchase agreements and/or other instruments. When the Fund engages in transactions that have a leveraging effect on the Funda�s portfolio, the value of the Fund will be more volatile and all other risks will tend to be compounded. This value excludes the Funda�s exposure to leverage indirectly through the Fund's investment in the Master Fund. The Fund does not intend to incur additional direct leverage at the Fund level to the extent that its existing direct leverage at the Fund level and its implicit leverage through its investment in the Master Fund exceeds 33 1a"3% of the Funda�s total assets, plus the amount of any implicit leverage at the Master Fund level attributable to the Funda�s investment in the Master Fund.

Western Asset Mortgage Defined Opportunity Fund Inc., a non-diversified closed-end investment management company traded on the New York Stock Exchange under the symbol aDMOa, is advised by Legg Mason Partners Fund Advisor, LLC (aLMPFAa), a wholly owned subsidiary of Legg Mason, Inc. (aLegg Masona), and is sub-advised by Western Asset Management Company (aWAMa), an affiliate of the advisor. Wilshire Associates Incorporated, an investment adviser unaffiliated with Legg Mason, LMPFA and WAM, serves as the Funda�s allocation subadviser.

All investments are subject to risks, including the possible loss of principal. The Fund's investments are subject to liquidity risk, credit risk, inflation risk, and interest rate risk. Mortgage-backed securities are subject to additional risks, including prepayment risk, which can limit the potential gains in a declining interest rate environment. The Fund may invest in securities backed by subprime or distressed mortgages which involve a higher degree of risk and chance of loss. Leverage may result in greater volatility of NAV and the market price of common shares and increases a shareholdera�s risk of loss. The Fund is not guaranteed by the U.S. Government, the U.S. Treasury, or any government agency. The credit quality ratings shown may change over time.

Data and commentary provided in this press release are for informational purposes only. Legg Mason and its affiliates do not engage in selling shares of the Fund.

The U.S. Department of the Treasury has not participated in the preparation of this release or the prospectus or made any representation regarding, and expressly disclaims any liability or responsibility to any investor in the Fund for, the accuracy, completeness or correctness of any of the information contained herein or therein. Without limitation of the foregoing, the U.S. Department of the Treasury does not approve or disapprove of any tax disclosure or advice set forth herein or therein.

FN1011937

Contributing Sources

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Western Asset Mortgage Defined Opportunity Fund Inc. as of December 31, 2010