The effect of the support, Al2O3, ZrO2, and SiO2, on the activity for CO oxidation of a series of CuO and CeO2 monometallic and bimetallic catalysts was studied. The catalysts were prepared by coimpregnation of the support with the adequate amount of Cu and Ce nitrates to obtain a loading of 2% Cu and/or 8% Ce. It was found that the support has a strong influence on the activity of the different bimetallic catalysts. Interestingly, the SiO2 supported catalyst shows the higher activity. The bimetallic supported catalysts follow the activity sequence CuO-CeO2/SiO2 > CuO-CeO2/ZrO2 > CuO-CeO2/Al2O3. In the absence of CeO2, the most active monometallic catalyst was the CuO/ZrO2 system. The different degree of interaction between CuO and CeO2 particles, induced by the support, can explain the activity results for the bimetallic catalysts. (C) 2008 Elsevier B.V. All rights reserved.