A Pt/Ce0.64Zr0.16Bi0.20O1.90/gamma-Al2O3 catalyst was prepared in order to establish complete oxidation of ethylene at temperatures below 100 degrees C. Ethylene was completely oxidized over the catalyst as low as at 65 degrees C, while over Pt/gamma-Al2O3, which has been well known as an active oxidation catalyst, complete oxidation was achieved at 145 degrees C.