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                                                                    EXHIBIT 31.2

                            SECTION 302 CERTIFICATION

I, Brian C. Henry, certify that:

1.       I have reviewed this report on Form 10-Q of Onyx Software Corporation;

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 Onyx as of, and for, the periods presented in this report;

4.       Onyx'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)) for Onyx 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 Onyx, including it consolidated subsidiaries, is made known
                  to us by others within those entities, particularly during the
                  period in which this report is being prepared;

         (b)      Evaluated the effectiveness of Onyx'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

         (c)      Disclosed in this report any change in Onyx's internal control
                  over financial reporting that occurred during Onyx's most
                  recent fiscal quarter (Onyx's fourth fiscal quarter in the
                  case of an annual report) that has materially affected, or is
                  reasonably likely to materially affect, Onyx's internal
                  controls over financial reporting; and

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

         (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
                  Onyx'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 Onyx's
                  internal control over financial reporting.

Date:  August 9, 2004

                                        By:           /s/ Brian C. Henry
                                                 ----------------------------
                                                        Brian C. Henry
                                                 Executive Vice President and
                                                   Chief Financial Officer