Disclosure Required by Section 303A.11 of NYSE's Listed Company Manual

As of February 10, 2009

As a Canadian reporting issuer with Common Shares listed on the Toronto Stock Exchange (TSX), MDS has in place a system of corporate governance practices which is responsive to applicable Canadian requirements, including the Corporate Governance Guidelines of the Ontario Securities Commission, National Policy 58-201 (the Guidelines).

MDS's corporate governance practices meet or exceed the Guidelines and all other applicable Canadian requirements. Reference is made to pages 43 to 48 (Schedule C) of MDS's management proxy circular, which contains a description of our system of corporate governance practices with reference to each of the Guidelines.

MDS is classified as a foreign private issuer under US securities law and its Common Shares are listed on the New York Stock Exchange (NYSE). Pursuant to the rules of the NYSE (the NYSE Rules), a foreign private issuer is permitted to follow home country practice, except for sections 303A.06 (must have an Audit Committee that satisfies the requirements of Rule 10A-3 under the Exchange Act); 303A.11 (must disclose any significant ways in which its corporate governance practices differ from those followed by domestic companies under NYSE listing standards); and 303A.12(b) (CEO must notify the NYSE in writing of any material non-compliance with any applicable provisions of Section 303A) of the NYSE Rules. MDS is in compliance with these sections. In addition, MDS benchmarks its policies and procedures against both Canadian and US governance standards, with a view to adopting best practices when appropriate to its circumstances. The Company's governance system incorporates many practices described in the NYSE Rules, and is in compliance with applicable rules adopted by the US Securities & Exchange Commission to give effect to provisions of the Sarbanes-Oxley Act of 2002.

The following is a summary of the only significant way in which MDS's corporate governance practices differ from those required to be followed by U.S. domestic issuers under the NYSE's listing standards:

Section 303A.08 of the NYSE's Listed Company Manual requires shareholder approval of all equity-compensation plans and material revisions. The definition of "equity-compensation plans" covers plans that provide for the delivery of newly issued securities, as well as plans which rely on securities reacquired on the market by the listed company for the purpose of redistribution to employees and Directors. The TSX rules provide that only the creation of, or amendment to equity-compensation plans which provide for issuances from treasury of securities of the listed company are subject to shareholder approval. MDS is in compliance with the rules of the TSX.