The effect of preparation method and pretreatment on the characteristic properties and selective CO oxidation activities of 50/50 CuO/CeO2, 25/25/50 CuO/Co3O4/CeO2 and 5/95 CuO/CeO2 catalysts was investigated. Catalysts were characterized by BET surface area measurement, N-2 physisorption, SEM micrographs and X-ray diffraction. The selective oxidation reaction in H-2 rich stream was carried out between the 110 degrees C and 210 degrees C temperatures. The 5/95 CuO/CeO2 catalysts gave the best CO conversion and selectivity result. The 5/95 CuO/CeO2 catalyst calcined at 700 degrees C protected its activity and selectivity at 200 degrees C during 24 h. (C) 2009 Elsevier B.V. All rights reserved.