CERTIFICATION


PURSUANT
TO SECTION 302 OF THE SARBANES-OXLEY ACT OF 2002





I ,
Stephen P. DeFalco, certify that:




1.   I have
reviewed this annual report on Form 40-F (the "Report") of MDS Inc. (the
"Registrant");
  2.   Based on
my knowledge, this Report does not contain any untrue statement of a material
fact or omit to state a material fact necessary to make the statements made, in
light of the circumstances under which such statements were made, not misleading
with respect to the period covered by this Report;
  3.   Based on
my knowledge, the financial statements, and other financial information included
in this Report, fairly present in all material respects the financial condition,
results of operations and cash flows of the Registrant as of, and for, the
periods presented in this Report;
  4.   The
Registrant’s other certifying officer and I are responsible for establishing and
maintaining disclosure controls and procedures (as defined in Exchange Act
Rules 13a-15(e) and 15d-15(e)) and internal control over financial
reporting (as defined in Exchange Act Rules 13a-15(f) and 15d-15(f)) for
the Registrant and have:
  (a) Designed
such disclosure controls and procedures, or caused such disclosure controls and
procedures to be designed under our supervision, to ensure that material
information relating to the Registrant, including its consolidated subsidiaries,
is made known to us by others within those entities, particularly during the
period in which this Report is being prepared;
  (b) Designed
such internal control over financial reporting, or caused such internal control
over financial reporting to be designed under our supervision, to provide
reasonable assurance regarding the reliability of financial reporting and the
preparation of financial statements for external purposes in accordance with
generally accepted accounting principles;
  (c) Evaluated
the effectiveness of the Registrant’s disclosure controls and procedures and
presented in this Report our conclusions about the effectiveness of the
disclosure controls and procedures, as of the end of the period covered by this
Report based on such evaluation; and
  (d) Disclosed
in this Report any change in the Registrant’s internal control over financial
reporting that occurred during the period covered by this Report that has
materially affected, or is reasonably likely to materially affect, the
Registrant’s internal control over financial reporting; and
  5.   The
Registrant’s other certifying officer and I have disclosed, based on our most
recent evaluation of internal control over financial reporting, to the
Registrant’s auditors and the audit committee of the Registrant’s board of
directors (or persons performing the equivalent functions):
  (a) All
significant deficiencies and material weaknesses in the design or operation of
internal control over financial reporting which are reasonably likely to
adversely affect the Registrant’s ability to record, process, summarize and
report financial information; and
  (b) Any
fraud, whether or not material, that involves management or other employees who
have a significant role in the Registrant’s internal control over financial
reporting.







Date:  January  29,
      2009
            /s/
      Stephen P. DeFalcoName:         Stephen
      P. DeFalco
              Title:           President
      and Chief Executive Officer










CERTIFICATION


PURSUANT TO SECTION 302 OF THE
SARBANES-OXLEY ACT OF 2002




I, Douglas S.
Prince, certify that:




1.   I have
reviewed this annual report on Form 40-F (the "Report") of MDS Inc. (the
"Registrant");




2.   Based on
my knowledge, this Report does not contain any untrue statement of a material
fact or omit to state a material fact necessary to make the statements made, in
light of the circumstances under which such statements were made, not misleading
with respect to the period covered by this Report;




3.   Based on
my knowledge, the financial statements, and other financial information included
in this Report, fairly present in all material respects the financial condition,
results of operations and cash flows of the Registrant as of, and for, the
periods presented in this Report;




4.   The
Registrant’s other certifying officer and I are responsible for establishing and
maintaining disclosure controls and procedures (as defined in Exchange Act
Rules 13a-15(e) and 15d-15(e)) and internal control over financial
reporting (as defined in Exchange Act Rules 13a-15(f) and 15d-15(f)) for
the Registrant and have:




(a) Designed
such disclosure controls and procedures, or caused such disclosure controls and
procedures to be designed under our supervision, to ensure that material
information relating to the Registrant, including its consolidated subsidiaries,
is made known to us by others within those entities, particularly during the
period in which this Report is being prepared;




(b) Designed
such internal control over financial reporting, or caused such internal control
over financial reporting to be designed under our supervision, to provide
reasonable assurance regarding the reliability of financial reporting and the
preparation of financial statements for external purposes in accordance with
generally accepted accounting principles;




(c) Evaluated
the effectiveness of the Registrant’s disclosure controls and procedures and
presented in this Report our conclusions about the effectiveness of the
disclosure controls and procedures, as of the end of the period covered by this
Report based on such evaluation; and




(d) Disclosed
in this Report any change in the Registrant’s internal control over financial
reporting that occurred during the period covered by this Report that has
materially affected, or is reasonably likely to materially affect, the
Registrant’s internal control over financial reporting; and




5.   The
Registrant’s other certifying officer and I have disclosed, based on our most
recent evaluation of internal control over financial reporting, to the
Registrant’s auditors and the audit committee of the Registrant’s board of
directors (or persons performing the equivalent functions):




(a) All
significant deficiencies and material weaknesses in the design or operation of
internal control over financial reporting which are reasonably likely to
adversely affect the Registrant’s ability to record, process, summarize and
report financial information; and




(b) Any
fraud, whether or not material, that involves management or other employees who
have a significant role in the Registrant’s internal control over financial
reporting.






Date:  January  29,
      2009
            /s/
      Douglas S. PrinceName:          Douglas
      S. Prince
              Title:           
      Executive Vice-President, Finance
              and Chief Financial
      Officer