Uniform hollow spherical rhombohedral LaMO₃ and solid spherical cubic MO_x (M = Mn and Co) NPs were fabricated using the PMMA-templating strategy. Hollow spherical LaMO₃ and solid spherical MO_x NPs possessed surface areas of 21–33 and 21–24 m²/g, respectively. There were larger amounts of surface-adsorbed oxygen species and better low-temperature reducibility on/of the hollow spherical LaMO₃ samples than on/of the solid spherical MO_x samples. Hollow spherical LaMO₃ and solid spherical MO_x samples outperformed their nanosized counterparts for oxidation of CO and toluene, with the best catalytic activity being achieved over the solid spherical Co₃O₄ sample for CO oxidation (T_50% = 81 °C and T_90% = 109 °C) at space velocity = 10 000 mL/(g h) and the hollow spherical LaCoO₃ sample for toluene oxidation (T_50% = 220 °C and T_90% = 237 °C) at space velocity = 20 000 mL/(g h). It is concluded that the higher surface areas and oxygen adspecies concentrations and better low-temperature reducibility are responsible for the excellent catalytic performance of the hollow spherical LaCoO₃ and solid spherical Co₃O₄ NPs. We believe that the PMMA-templating strategy provides an effective route to prepare uniform perovskite-type oxide and transition-metal oxide NPs.