Nanocrystalline Ce0.8Gd0.2O2-delta powder has been prepared from a homogeneous precipitation system using hexamethylenetetramine as a precipitant. The powder characteristics, sinterability and mechanical properties have been examined. The powder calcined at 700-800degreesC has an optimal sinterability, and can be sintered to nearly full density (> 99.0% relative density) at a temperature as low as 1250 degreesC. Dense Ce0.8Gd0.2O2-delta ceramics (> 97.0% relative density) with grain size range of - 0.5-9.5 mum can be obtained by controlling sintering temperature and time. The ceramic with a mean grain size of - 2.63 mum has a fracture toughness of - 1.53 +/- 0.2 MPam(1/2); and no fracture toughness dependence of grain size (-0.5-9.5mum) has been found in this study for dense Ce0.8Gd0.2O2-delta ceramics. (C) 2004 Elsevier B.V All rights reserved.