The catalytic reduction of NO with CO was investigated in the presence of oxygen over 16 supported metallic catalysts. Ir/WO3 Ir/ZnO, and Rh/Al2O3 showed the pronounced activity even in excess amount of oxygen. The effect of preparation conditions on the activity of Ir catalysts was further studied and it was found that Ir/WO3 prepared by loading of H2IrCl6 at 0.5 wt % Ir is the most active for the NO reduction with CO.