TiO2-supported Pt-Fe (Pt-Fe/TiO2) catalysts were prepared by impregnation methods from metal acetylacetonate complexes, followed by oxidation at 400 A degrees C and H-2 reduction at 200 A degrees C. The Pt-Fe/TiO2 catalysts prepared by coimpreganation exhibited much higher activity for CO oxidation than Pt/TiO2 catalyst under dilute O-2 condition ([O-2]/[CO] = 0.5). The CO oxidation activity of the Pt-Fe/TiO2 catalyst was affected by the preparation conditions. The close proximity between Pt and Fe was crucial to obtaining the enhanced catalytic activities. FTIR studies revealed that no strong electronic interaction was observed for Pt-Fe sites and that the oxidative desorption of the adsorbed CO species on Pt was promoted by the presence of Fe.