High-quality nano-sized Ce0.8Gd0.2-xDyxO2-delta (0 <= x <= 0.2) powders are synthesized by a solution combustion process. The calcined powders are composed of a ceria-based single phase with a cubic fluorite structure and are nanocrystalline nature, i.e., 15-24 nm in crystallite size. The addition of an intermediate amount of Dy3+ (0.03 <= x <= 0.16) for Gd3+ in Ce0.8Gd0.2O2-delta decreases the electrical conductivity. On the other hand, the doping of a small amount of Dy3+ (0.01 <= x <= 0.02) and of a large amount of Dy3+ (0.17 <= x <= 0.19) leads to an increase in conductivity. The Ce0.8Gd0.2-xDyxO2-delta shows the highest electrical conductivity (0.215 S cm(-1)) at 800 degrees C. 0 2011 Elsevier B.V. All rights reserved.