Oxidation of ethane, propane and n-butane on chromium oxide supported on alumina and on unsupported chromia yields carbon oxides as the main reaction products. The selectivity to olefins, the oxidative dehydrogenation products does not exceed about 8% at 10% conversion for propane and n-butane and 1% for the ethane reaction. Oxidative dehydrogenation is the main reaction for the isobutane reaction, the latter hydrocarbon showing, moreover, the highest overall activity. The TPD experiments show that the adsorbed alkane species desorb in the form of CO2 and H2O, only traces of olefins being observed.