To obtain a highly active and low-cost oxygen reduction electrode, as compared with a Pt-loaded carbon electrode, a nano-sized La-Mn-based perovskite-type oxide on a carbon support was prepared through the reverse-micelle method. An gas diffusion oxygen reduction electrode using nano-sized La0.4Ca0.6Mn0.9Fe0.1O3 as a electrocatalyst allowed a electrode potential as high as -50 mV (vs Hg/HgO) in 9 mol/l NaOH at 500 mA cm(-2). This electrode potential is much higher than the electrode potential of carbon-supported Pt nanoparticles at the same current density. This result suggests that nano-sized La0.4Ca0.6Mn0.9Fe0.1O3 is a promising candidate as an alternative oxygen reduction catalyst of Pt nanoparticles. (C) 2011 The Electrochemical Society. [DOI: 10.1149/1.3561762] All rights reserved.