The partial oxidation of methane was studied over gamma-Al2O3-supported catalysts for Rh loadings between 0.01 and 5.0 wt%. It was found that the activity and selectivities for loadings between 0.5 and 5.0 wt% are almost the same. As an example, detailed information is presented for the 1.0 wt% Rh/gamma-Al2O3, which provides at 750(degrees)C (furnace temperature) an activity of 82% and selectivities of 96% to CO and 98% to H-2, at a gas hourly space velocity (GHSV) of 720000 ml g(-1) h(-1). Its activity remained stable during our experiment which lasted 120 h. Possible explanations for this high stability are proposed based on TPR and XRD experiments. Pulse reactions with small pulses of CH4 and CH4/O-2 (2/1) were performed over the reduced and unreduced Rh catalysts to probe the mechanistic aspects of the reaction. The partial oxidation of methane to syngas was found to be initiated by metallic rhodium sites, since the CO selectivity increased with increasing number of such sites.