Nanosized Pd doped and supported on Mn2O3 catalysts were prepared and tested for CO oxidation. The introduction of Pd in Mn2O3 enhances the activity for CO oxidation due to a synergistic effect. The supported samples showed total CO conversion at lower temperature as compared to doped samples, whereas pristine Mn2O3 showed total CO conversion at a much higher temperature. The presence of Pd greatly improved the catalytic activity for CO oxidation. The presence of moisture in the feed gas does not deactivate the catalysts for CO oxidation. XRD pattern substantiates the formation of Mn2O3 phase, SEM images show that the particles are in the nanosized range and roughly spherical in appearance. From TEM images, the average particle size was found to be around 50 nm. Thermal analysis data indicates the phase change from Mn2O3 to Mn3O4 beyond 900 °C and also gives information regarding the thermal stability of Mn2O3 after the incorporation of Pd in the lattice.