Effects of the addition of various transition metals to heteropoly compounds on the catalytic performance for oxidation of light alkanes were reviewed. The catalytic selective oxidation of isobutane, propane, and ethane proceeded and the performance was variously changed by the additives. The addition of iron effectively enhanced the catalytic performance under both oxygen-rich and -poor conditions, while copper was found to most enhance the catalytic performance under oxygen-poor conditions. It is suggested that the enhancement by the iron addition under oxygen-rich conditions is due to the promotion of reduction of catalyst and that the enhancement by the copper and iron addition under oxygen-poor conditions is due to the promotion of the reoxidation of the catalyst.