A-site cation-disordered/ordered perovskite oxide LaBaCoO was synthesized by sol-gel method. Disordered LaBaCoO has higher conductivities than the ordered counterpart due to higher concentration of charge carriers, and is more stable at temperatures up to 850 degrees C and in argon, air and oxygen. Different conduction behavior in air/oxygen and argon suggests a p-type to n-type conduction transition caused by changes in chemical defects and charge compensation mode. Two conduction transitions associated with thermal-driven reduction of Co4+ to Co3+ and Co3+ to Co2+ were observed in air and oxygen. High conductivities and long-term structural stabilities suggested that LaBaCoO is a promising material as solid oxide fuel cell cathode or oxygen permeation membrane. (C) 2011 Elsevier B.V. All rights reserved.