Solid-state reactions have the potential for direct preparation of ceramic powders and offer a low-temperature and low-cost alternative to conventional techniques for production of oxide powders. This paper describes a simple and effective mechanochemical method based on solid-state reactions during ball milling for synthesis of nanoscaled ceria (CeO2) particles. By using an organic base instead of an inorganic base, metal-ion-free nanoscaled CeO2 can also be made. The effects of annealing temperature on particle sizes and lattice strain are investigated. The results show that the average particle sizes of the particles increases and the average crystal lattice distortion decreases with the annealing temperature. Transmission electron microscopy examinations demonstrate that the CeO2 particles synthesised by this method are near-spherical shaped.