Rare earth and alkaline earth co-doped Ce0.85La0.10Ca0.05O2-delta electrolyte material with the powder obtained by solid-state reaction method was sintered at 1300, 1400, 1500 and 1600 degrees C respectively. The results showed that the ionic conductivity of the sample sintered at 1400 degrees C was slightly lower compared to that sintered at 1500 degrees C in the temperature range of 300-550 degrees C, while the sample sintered at 1400 degrees C showed the highest ionic conductivity in all the samples above 550 degrees C. The ionic conductivity of similar to 0.021 S/cm at 600 degrees C and the relative density of 98.2% were observed for the sample sintered at 1400 degrees C. In addition, the highest flexural strength with 145 MPa was also obtained for the sample sintered at 1400 degrees C. It suggested that the sintering temperature for Ce0.85La0.10Ca0.05O2-delta electrolyte may be reduced to as low as 1400 degrees C with desired properties. (C) 2010 Elsevier Ltd. All rights reserved.