Catalytic activities of various metal molybdates were tested for the gas-phase partial oxidation of propane with molecular oxygen under an atmospheric pressure in the temperature range 325-500 degrees C. Metal molybdate catalysts were found to mostly promote the oxidative dehydrogenation of propane to propene. More than 80% selectivity to propene was attained on each catalyst but their catalytic activities differed greatly. Of the catalysts, cobalt molybdate showed the highest catalytic performance for the oxidative dehydrogenation and the catalytic property strongly depended on the catalyst composition. Co0.95MoOx catalyst gave 60% selectivity to propene at 20% conversion of propane at 450 degrees C. The catalytic activity and selectivity of each catalyst in the propane oxidation is discussed in terms of surface acidity and reactivity of lattice oxide ions.