Mn-doped samples with atomic ratios equal to 0.5%, 1% and 3% were prepared by the conventional mixed-oxide method from commercial cerium oxide (CeO 2 ) and manganese oxide (MnO 2 ) powders. The effect of Mn doping on the densification behavior of CeO 2 was investigated by means of dilatometer and scanning electron microscopy (SEM). It was found that Mn doping reduced sintering temperature and promoted the grain growth dramatically. The sintering kinetics study indicated that under the isothermal sintering condition, the grain growth activation energy, Q, decreased from 731+/-61 kJ/mol for pure CeO 2 to 593+/-53 kJ/mol for 1% Mn-doped CeO 2 .