A novel single phase BaCe0.5Bi0.5O3 - δ (BCB) was employed as a cathode material for a proton-conducting solid oxide fuel cell (SOFC). The single cell, consisting of a BaZr0.1Ce0.7Y0.2O3 - δ (BZCY7)-NiO anode substrate, a BZCY7 anode functional layer, a BZCY7 electrolyte membrane and a BCB cathode layer, was assembled and tested from 600 to 700 °C with humidified hydrogen (∼3% H2O) as the fuel and the static air as the oxidant. An open-circuit potential of 0.96 V and a maximum power density of 321 mW cm-2 were obtained for the single cell. A relatively low interfacial polarization resistance of 0.28Ω cm2 at 700 °C indicated that the BCB was a promising cathode material for proton-conducting SOFCs. © 2009 Elsevier B.V. All rights reserved.