NATURAL GAS SERVICES GROUP, INC.


                                                                    EXHIBIT 99.2



                            CERTIFICATION PURSUANT TO
                               18 U.S.C. ss.1350,
                             AS ADOPTED PURSUANT TO
                  SECTION 906 OF THE SARBANES-OXLEY ACT OF 2002


         In connection with the Quarterly  Report of Natural Gas Services Group,
Inc. (the  "Company") on Form 10-QSB for the period ended September 30, 2002, as
filed with the  Securities  and  Exchange  Commission  on the date  hereof  (the
"Report"),  I, Earl R. Wait,  Chief Financial  Officer of the Company,  certify,
pursuant  to 18 U.S.C.  ss.1350,  as  adopted  pursuant  to  Section  906 of the
Sarbanes-Oxley Act of 2002, that:

         1.       The Report  fully  complies  with the  requirements of Section
                  13(a) or 15(d) of the Securities Exchange Act of 1934; and

         2.       The information  contained in the Report fairly  presents,  in
                  all material respects,  the financial condition and results of
                  operations of the Company.



                                                  /s/ Earl R. Wait
                                                 -------------------------------
                                                 Earl R. Wait
                                                 Chief Financial Officer

                                                 December 2, 2002