Gd2O3 doped CeO2 nanopowders were prepared under high temperature and pressure conditions by precipitation from metal nitrates with aqueous ammonium hydroxide. Spherical shape Gd2O3 doped CeO2 nanopowders were obtained By a reaction at the temperature range of 200°C – 230°C for 6 h. The average size and size distribution of the synthesized particles were below 10 nm and narrow, respectively. The XRD diffraction pattern shows that the synthesized powders were crystalline. This study has shown that the synthesis of Gd2O3 doped CeO2 nanopowders is possible under glycothermal conditions in ethylene glycol solution. The effects of synthesis parameters, such as the solvent ratio of starting solution, pH of starting solution, reaction temperature and time, are discussed.