Crystalline mesoporous metal oxides have attracted considerable attention recently, but their catalytic applications have rarely been studied. In this work, a series of crystalline three-dimensional mesoporous metal oxides (i.e., CeO2, Co3O4, Cr2O3, CuO, Fe2O3, beta-MnO2, Mn2O3, Mn3O4, NiO, and NiCoMnO4) were prepared using the mesoporous silica KIT-6 as a hard template. These ordered mesoporous metal oxides with highly crystalline walls were characterized by PXRD, TEM, N-2 adsorption and evaluated as CO oxidation catalysts. These mesoporous materials, except for mesoporous Fe2O3, exhibit much higher catalytic activities than their bulk counterparts. In particular, mesoporous Co3O4, beta-MnO2, and NiO show appreciable CO oxidation activity below 0 A degrees C, and the catalytic activities of mesoporous beta-MnO2, and NiO are even higher than those of their nanoparticulate counterparts with large surface areas. beta-MnO2 is particularly interesting because it combines low cost and low toxicity with high activity (T (50) = 39 A degrees C).