Hetero-structured interfaces of oxides, which can exhibit reactivity characteristics remarkably different from bulk oxides, are interesting systems to explore in search of highly active fuel cell catalysts for oxygen electrocatalysis. (001)-oriented La0.6Sr0.4CoO3-delta (LSC60-40(113)) thin films having thicknesses from tens to hundreds of nanometers were grown epitaxially on (001)-oriented yttria-stabilized zirconia (YSZ). Atomic force microscopy showed that all the film surfaces were of high quality with average surface roughness approximately one nanometer. The surface oxygen exchange kinetics of these films were determined by electrochemical impedance spectroscopy. While (001)-oriented LSC60-40(113) thin films were found to have similar surface oxygen exchange coefficients to LSC60-40(113) bulk, surface coverage of (001)-oriented (La0.5Sr0.5)(2)CoO4 +/-delta (LSC214) on the LSC60-40(113) thin films led to significant enhancement in the surface oxygen kinetics up to similar to 3 orders of magnitude. Interestingly, LSC214-decorated LSC60-40(113) films have comparable surface exchange kinetics (similar to 1.10(-5) cm.s(-1) at 550 degrees C) to similarly prepared LSC214-decorated La0.8Sr0.2CoO3-delta films. Such high surface oxygen kinetics are among the most active SOFC cathode materials reported to date. (C) 2012 The Electrochemical Society. [DOI: 10.1149/2.018207jes] All rights reserved.