GDC20(Ce 0.8 Gd 0.2 O 1.9) powder was synthesized from Ce and Gd nitrate solutions using ammonium carbonate((NH 4) 2 CO 3) as a precipitant. Attrition-milling of the powder, which had been calcined at 700 o C for 4 h, decreased an average particle size of 2.2 µm to 0.5 µm. The milled powder consisted of nano-sized spherical primary particles. Due to the excellent sinterability of the powder, sintering of the powder compacts for 4 h showed relative densities of 80% at 1000 o C and 96.5% at 1200 o C, respectively. Densification was found to almost complete at 1300 o C, resulting in a dense and homogeneous microstructure with a relative density of 99.5%. The grains of ~0.2 µm in size at 1200 o C grew to ~1 µm in size at 1300 o C as a result of a rapid grain growth.