BACKGROUND: Pt-free cathodic catalyst is needed for microbial fuel cells (MFCs). Perovskite-type oxide could be a substitute for Pt because it has been proved to be a highly active and low-cost oxygen reduction catalyst in chemical fuel cells. RESULTS: A nano-sized La0.4Ca0.6Co0.9Fe0.1O3 perovskite-type oxide on a carbon support (LCCF/C) was prepared and tested for its performance and stability (15 cycles) in MFCs. An exchange current density of 7.030 x 105 (A cm2) was obtained with fresh LCCF/C cathode and is increased to 7.438 x 105 (A cm2) after 15 cycles operating in MFCs. A power density of 405 mW m2 was achieved with the LCCF/C cathode at the 2nd cycle which was between those of Pt/C (560 mW m2) and C (339 mW m2) cathodes. At the end of the 15th cycle, the lowest decay (due to biofouling) rate on the open circuit voltage (2%) and the maximum power density (15%) were observed with LCCF/C cathode compared with those of Pt/C (4%, 17%) and C (22%, 69%) cathodes, respectively. CONCLUSIONS: This study demonstrated that perovskite-type oxide on carbon support catalysts could be a potential substitute for Pt for cathodic oxygen reduction reaction (ORR) in air-cathode MFCs. (c) 2012 Society of Chemical Industry