Preliminary irradiation of ZnO with 60Co γ-radiation in air is found to enhance its catalytic activity for the free radical oxidation reaction of secondary alcohols by CCl4. The enhanced catalytic activity is found to be permanent and is a function of the γ-dose. The radiation damage caused in ZnO due to γ-irradiation increases the concentration of O-2(ads) on the surface of ZnO and this is responsible for the enhanced catalytic activity of γ-irradiated ZnO. © 1982.