EXHIBIT 31.2
CERTIFICATION
I, Randall J. Weisenburger, certify that:
1. I have reviewed this Annual Report on Form 10-K for the period ended
December 31, 2005 of Omnicom Group Inc.;
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 annual 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 registrant's most recent fiscal quarter (the
registrant's fourth fiscal quarter in the case of our
annual 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: February 24, 2006 /s/ Randall J. Weisenburger
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Randall J. Weisenburger
Executive Vice President and
Chief Financial Officer