Nanostructured CeO₂ supported CuO–MnO₂ (CuMn/Ce) catalysts were synthesized by wet co-impregnation method and compared with CuO/CeO₂ and MnO₂/CeO₂ catalysts on CO oxidation. The former shows significantly higher catalytic activity toward CO oxidation than the bimetallic oxides catalysts with minimum T₅₀. Dual synergistic effects in the interfaces of CuO–MnO₂ and CuO–CeO₂ shall be responsible for the higher oxidation performance of CuMn/Ce catalyst. As Cu/Mn mass ratio varies from 1/0.2 to 1/9, CO oxidation activities of the catalysts present unimodal distribution, and the catalyst with Cu/Mn = 1/1 shows the highest performance (T₅₀ = 45.8 °C; Ea = 24.11 kJ mol⁻¹). Cu acts as CO dissociative adsorption sites, and Mn–Ce supplies activated O species from gas molecule and lattice oxygen, which are both indispensable for improving utilization efficiency of the reactants in the dual redox processes. The catalytic performance of catalyst is also vitally correlated with calcination temperature (160–320 °C). The optimum calcination temperature of CuMn/Ce catalyst is 320 °C. Catalyst characterization results indicate that the pretreatment at 320 °C is decent to obtain desired metal oxides along with fine texture properties.