SUB-INVESTMENT ADVISORY AGREEMENT

AGREEMENT dated January 31, 2008, among BlackRock Defined Opportunity Credit Trust, a Delaware statutory trust (the ?Trust?), BlackRock Advisors, LLC, a Delaware limited liability company (the ?Advisor?), and BlackRock Financial Management, Inc., a Delaware corporation (the ?Sub-Advisor?).

WHEREAS, the Advisor has agreed to furnish investment advisory services to the Trust, a closed-end management investment company registered under the Investment Company Act of 1940, as amended (the ?1940 Act?);

WHEREAS, the Advisor wishes to retain the Sub-Advisor to provide it with certain sub-advisory services as described below in connection with Advisor?s advisory activities on behalf of the Trust;

WHEREAS, the investment management agreement between the Advisor and the Trust, dated December 17, 2007 (such agreement or the most recent successor agreement between such parties relating to advisory services to the Trust is referred to herein as the ?Advisory Agreement?), contemplates that the Advisor may appoint a sub-adviser to perform investment advisory services with respect to the Trust; and

WHEREAS, this Agreement has been approved in accordance with the provisions of the 1940 Act, and the Sub-Advisor is willing to furnish such services upon the terms and conditions herein set forth;

NOW, THEREFORE, in consideration of the mutual premises and covenants herein contained and other good and valuable consideration, the receipt of which is hereby acknowledged, it is agreed by and between the parties hereto as follows:

1.             Appointment.  The Advisor hereby appoints the Sub-Advisor to act as sub-advisor with respect to the Trust and the Sub-Advisor accepts such appointment and agrees to render the services herein set forth for the compensation herein provided.

2.             Services of the Sub-Advisor.  Subject to the succeeding provisions of this section, the oversight and supervision of the Advisor and the direction and control of the Trust?s Board of Trustees, the Sub-Advisor will perform certain of the day-to-day operations of the Trust, which may include one or more of the following services, at the request of the Advisor:  (a) acting as investment advisor for and managing the investment and reinvestment of those assets of the Trust as the Advisor may from time to time request and in connection therewith have complete discretion in purchasing and selling such securities and other assets for the Trust and in voting, exercising consents and exercising all other rights appertaining to such securities and other assets on behalf of the Trust; (b) arranging, subject to the provisions of paragraph 3 hereof, for the purchase and sale of securities and other assets of the Trust; (c) providing investment research and credit analysis concerning the Trust?s investments, (d) assist the Advisor in determining what portion of the Trust?s assets will be invested in cash, cash equivalents and money market instruments, (e) placing orders for all purchases and sales of such investments