A cobalt-free perovskite oxide, Ba0.5Sr0.5Zn0.2Fe0.8O3-delta (BSZF), was investigated as a novel cathode material for intermediate-temperature solid-oxide fuel cells (IT-SOFCs). Room-temperature nonstoichiometry of BSZF was as high as 0.412, which was favorable for oxygen-reduction reaction. At 700 degrees C, the polarization resistances were as low as 0.22 and 0.13 Omega.cm(2), respectively, for pure and impregnated BSZF cathodes under open-circuit conditions, suggesting that oxygen-deficient BSZF was a promising cathode candidate for IT-SOFCs.