The reaction of methane with surface oxygen as well as the interaction of methane/oxygen mixtures with a Rh(1 wt%)/gamma-Al2O3 catalyst was studied by applying the temporal-analysis-of-product (TAP) reactor. The product distribution was strongly affected by the degree of surface reduction. CO2 is formed as a primary product via a redox mechanism with the participation of surface oxygen. The dehydrogenation of methane yielding carbon deposits on the surface occurs on reduced surface sites. The formation of CO proceeds with high selectivity (up to 96%) at 1013 K via fast reaction of surface carbon species with CO2.