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I, Christopher P. Kiritsy, Chief Financial Officer of Kos Pharmaceuticals,
Inc., certify that:



|1. |  | I have reviewed this annual report on Form 10-K of Kos
Pharmaceuticals, Inc;                                                                                                                                                                                                                                           
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|2. |  | Based on my knowledge, this annual 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 the statements were made, not misleading with respect to
the period covered by this annual report;
|  
|3. |  | Based on my knowledge, the financial statements, and other
financial information included in this annual 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 annual report;                  
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|4. |  | The registrants other certifying officers and I are responsible
for establishing and maintaining disclosure controls and procedures (as
defined in Exchange Act Rules 13a-15e and 15d-15(e)) for the registrant
and we 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; 
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| |  |  | b. 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                                                                                                 
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| |  |  | c. 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 the annual report) that has
materially affected, or is reasonably likely to materially
affect, the registrants internal control over financial
reporting.



|5. |  | The registrants other certifying officers 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
function):
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| |  |  | a. all significant deficiencies and material weaknesses in
the design or operation of internal control which are reasonably
likely to adversely affect the registrants ability to record,
process, summarize and report financial information; and
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| |  |  | b. any fraud, whether or not material, that involves
management or other employees who have a significant role in the
registrants internal controls over financial reporting.                                                                     

Date: March 15, 2004

/s/ Christopher P. Kiritsy

Christopher P. Kiritsy
Chief Financial Officer