The electrochemical performances of proton-conducting SOFCs with the perovskite-type oxide cathodes were investigated at low temperature of 773 K. Among the perovskite-type oxides used in the present study. La0.7Sr0.3FeO3 (LSF) cathode exhibited the lowest overpotential at 773 K. The power density of the SOFC was dependent on the particle size of LSF cathode. The decrease in the particle size resulted in the decrease in over potential. The Power density of the cell with LSF cathode was also dependent on the thickness of LSF cathode; in the present condition, the LSF cathode with 13-mu m thickness showed the best electrochemical performance at 773 K. (C) 2010 Elsevier B.V. All rights reserved.