<PAGE>

                                                                    EXHIBIT 31.2


                           CERTIFICATION PURSUANT TO
                            15 U.S.C. SECTION 7241,
                             AS ADOPTED PURSUANT TO
                               SECTION 302 OF THE
                           SARBANES-OXLEY ACT OF 2002


I, Michael E. Boxer, certify that:

1.       I have reviewed this annual report on Form 10-K of Mariner Health Care,
         Inc.;

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
         such 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;

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-15(e) and 15d-15(e)) for the
         registrant and we have:

         a)       designed such disclosure controls and procedures 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)       evaluated the effectiveness of the registrant's disclosure
                  controls and procedures and presented in this annual report
                  our conclusions about the effectiveness of the disclosure
                  controls and procedures, as of the end of the period covered
                  by this annual report based on such evaluation;

         c)       disclosed in this annual report any change in the registrant's
                  internal controls that occurred during the registrant's fourth
                  fiscal quarter that has materially affected, or is reasonably
                  likely to materially affect, the registrant's internal
                  controls; and

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

         a)       all significant deficiencies in the design or operation of
                  internal controls which could adversely affect the
                  registrant's ability to record, process, summarize and report
                  financial data and have identified for the registrant's
                  auditors any material weaknesses in internal controls; and

         b)       any fraud, whether or not material, that involves management
                  or other employees who have a significant role in the
                  registrant's internal controls.



Date: March 15, 2004


                          /s/ Michael E. Boxer
                          ----------------------------------------------------
                          Michael E. Boxer
                          Executive Vice President and
                          Chief Financial Officer (Principal
                          Financial Officer)