Oxidation studies have been carried out on 11.5 to 12.0 g/cm3 density uranium monocarbide microspheres and on mixed 11.96 to 12.04 g/cm3 density uranium-plutonium carbide pellets under various oxygen partial pressures in the 550 to 745 K temperature range. Oxidation of UC and (U,Pu)C produced a U3O8 [oxygen-to-metal ratio (O/M) = 2.66] and (U,Pu)O2 (O/M = 2.15), respectively, with a carbon content of <600 ppm. The surface area of the resultant oxides as determined by the Brunauer-Emmett-Teller method are 1 to 2 and 4 to 5 m2/g, respectively. The oxidized products were suitable for wet and dry recycle.