Cu-based mixed oxides were investigated for WGSR in order to identify catalysts with high activity and durability even under severe conditions including a large amount of H2O in the reformed fuels. CuAl2O4 and CuMn2O4 showed much higher specific rates of CO conversion than Cu/ZnO/Al2O3. Although WGSR activity emerged from reduction of the mixed oxides, high-temperature reduction gave rise to the sintering of Cu. CuAl2O4 showed moderate CO oxidation activity at lower temperatures and WGSR activity over 300degreesC. The CuMn2O4 catalyst exhibited high WGSR activity over 225degreesC, comparable to that of Cu/ZnO/Al2O3, and high durability for 20 h at 200-225 degreesC.