**Exhibit 31.2**

 

**Certification of Principal Financial OfficerPursuant to Section 302 of the Sarbanes-Oxley Act of 2002**

 

I,Philip R. Jacoby, Jr. certify that:

 

1.                                       I have reviewed this QuarterlyReport on Form 10-Q of Osiris Therapeutics, Inc.

 

2.                                       Based on my knowledge, thisreport does not contain any untrue statement of a material fact or omit tostate a material fact necessary to make the statements made, in light of thecircumstances under which such statements were made, not misleading withrespect to the period covered by this report;

 

3.                                       Based on my knowledge, thefinancial statements, and other financial information included in this report,fairly present in all material respects the financial condition, results ofoperations and cash flows of the registrant as of, and for, the periodspresented in this report;

 

4.                                       The registrant’s othercertifying officer(s) and I are responsible for establishing andmaintaining disclosure controls and procedures (as defined in Exchange Act Rules 13a-15(e) and15d-15(e)) and internal control over financial reporting (as defined inExchange Act Rules 13a-15(f) and15d-15(f)) for the registrant and have:

 

(a)                          Designedsuch disclosure controls and procedures, or caused such disclosure controls andprocedures to be designed under our supervision, to ensure that materialinformation relating to the registrant, including its consolidatedsubsidiaries, is made known to us by others within those entities, particularlyduring the period in which this report is being prepared;

 

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

 

(c)                          Evaluated the effectiveness of theregistrant’s disclosure controls and procedures and presented in this reportour conclusions about the effectiveness of the disclosure controls andprocedures, as of the end of the period covered by this report based on suchevaluation; and

 

(d)                         Disclosed in this report any change inthe registrant’s internal control over financial reporting that occurred duringthe registrant’s most recent fiscalquarter (the registrant’s fourth fiscal quarter in the case of an annualreport) that has materially affected, or is reasonably likely to materiallyaffect, the registrant’s internal control over financial reporting; and

 

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

 

(a)                          Allsignificant deficiencies and material weaknesses in the design oroperation of internal control over financial reporting which are reasonablylikely 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 theregistrant’s internal control over financialreporting.

 

Date:May 22, 2008, intended to be effective as of May 12, 2008

 
|   | /s/  PHILIP R. JACOBY, JR.       |
|--------|----------------------------------|
|   | Philip  R. Jacoby, Jr.      |
|   | Interim  Chief Financial Officer |

 

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