JOINT FILING AGREEMENT Pursuant to Rule 13d-1(k)(1) under the Securities Exchange Act of 1934, the undersigned hereby agree that only one statement containing the information required by Schedule 13D (or any amendment thereof) need be filed on their...

                                  EXHIBIT 99.A


                             JOINT FILING AGREEMENT

         Pursuant to Rule 13d-1(k)(1) under the Securities Exchange Act of 1934,
the undersigned hereby agree that only one statement  containing the information
required  by  Schedule  13D (or any  amendment  thereof)  need be filed on their
behalf with  respect to the  beneficial  ownership of any equity  securities  of
Criticare Systems, Inc. or any subsequent acquisitions or dispositions of equity
securities of Criticare Systems, Inc. by any of the undersigned.

Dated:  March 9, 2001


                            (Signature Page Follows)





                   Signature Page 1 to Joint Filing Agreement


                               OXFORD BIOSCIENCE PARTNERS III LP
                               By:     OBP Management III LP


                               By:     /s/ Xxxxxxx X. Xxxxxx
                                       General Partner


                               OXFORD BIOSCIENCE PARTNERS (ADJUNCT) III LP
                               By:     OBP Management III LP


                               By:     /s/ Xxxxxxx X. Xxxxxx
                                       General Partner


                               OXFORD BIOSCIENCE PARTNERS (BERMUDA) III
                               LIMITED PARTNERSHIP
                               By: OBP Management III (Bermuda) Limited
                                   Partnership


                               By:     /s/ Xxxxxxx X. Xxxxxx
                                       General Partner


                               mRNA FUND L.P.
                               By:     mRNA PARTNERS L.P.


                               By:     /s/ Xxxxxxx X. Xxxxxx
                                       General Partner

                               OBP Management III LP


                               By:     /s/ Xxxxxxx X. Xxxxxx
                                       General Partner


                               OBP Management III (Bermuda) Limited Partnership


                               By:     /s/ Xxxxxxx X. Xxxxxx
                                       General Partner


                                      -2-




                   Signature Page 2 to Joint Filing Agreement




                               mRNA PARTNERS L.P.


                               By:     /s/ Xxxxxxx X. Xxxxxx
                                       General Partner


                                       /s/ Xxxxxxxx X. Xxxxxxx
                                       Xxxxxxxx X. Xxxxxxx


                                       /s/ Xxxxxxx X. Xxxxxx
                                       Xxxxxxx X. Xxxxxx


                                       /s/ Xxxx X. Xxxxxx
                                       Xxxx X. Xxxxxx


                                       /s/ Xxxxxxx X. Xxxxxxx
                                       Xxxxxxx X. Xxxxxxx


                                      -3-