The co-precipitation technique renders an excellent route to obtain a homogeneous mixture of ThO₂ and UO₂ powders. In this process, after the nitrate solutions of Th and U are mixed in the intended ratio, oxalic acid is added for co-precipitation. The precipitate is then dried and calcined to get a solid solution of ThO₂ and UO₂. In this study, ThO₂–30%UO₂ and ThO₂–50%UO₂ (% in weight) powders were characterized in terms of particle size, particle shape, surface area, phase content, O/M ratio etc. The pellets obtained by sintering these powders were characterized with the help of optical microscopy, scanning electron microscopy (SEM) and electron probe microanalysis (EPMA). The XRD data for ThO₂–30%UO₂ and ThO₂–50%UO₂ pellets showed the presence of a small amount of U3O8 phase besides fluorite phase. The grain size of ThO₂–30%UO₂ and ThO₂–50%UO₂ was found to be 5.7 and 4.5 µm, respectively.