The oxidation of methane has been studied in the temperature range 475 degreesC less than or equal to T less than or equal to 660 degreesC isothermally using Mn-substituted barium hexaaluminate catalysts. The solid material was characterized by BET, XRD and TPD of oxygen. Reproducible oxidation rates are provided and the effects of varying both methane (3.8-18.8 Torr) and oxygen (22.8-114 Torr) partial pressure at various reaction temperatures are presented to generate experimental databases. The suitability of several kinetic expressions, which is based on reaction mechanisms that have been advanced in the literature to represent the experimental data was assessed. On the whole, several mechanistic models provided an adequate fit to the entire experimental data sets. Appreciable deviations of the predicted from the actual reaction rates have allowed us to discriminate between the various mechanistic models. The best description was obtained for a model featuring a two-step reaction sequence on a nonuniform surface.