A single-step infiltration method has been developed to incorporate the La0.85Sr0.15MnO3-delta (LSM) oxide phase into a pre-sintered, porous yttria-stabilized zirconia (YSZ) network, forming an effective LSM-YSZ composite cathode. The LSM particles, with a size of similar to 30 to similar to 100 nm, deposit preferentially on the pore walls throughout the porous YSZ, forming a pathway for electron conduction, and creating a high density of active sites for the oxygen reduction reaction. The resulting composite cathode has been evaluated in a solid oxide fuel cell operating at 923 K, and demonstrated the effectiveness of the infiltration process. The single-step infiltration method enables the possibility of producing solid oxide fuel cell cathodes, based on pre-sintered porous YSZ networks, with other catalysts that are not compatible with the high temperature processing that co-firing may require. (c) 2006 The Electrochemical Society.