The mechanism of operation of a single chamber solid oxide fuel cell (SOFC), where a mixture of fuel and oxidant is utilized, is not completely understood. In this study, electrolyte supported single chamber SOFCs consisting of lanthanum strontium cobalt ferrite cathode, yttria stabilized zirconia (YSZ) electrolyte and nickel cermet anode have been fabricated and investigated in the intermediate temperature range (500-700 degreesC) using propane-air mixtures as fuel. An attempt has been made to separate the cathode and anode overpotentials on the fuel cell performance using impedance spectroscopy and utilizing different anode compositions. Low and high frequency relaxations of impedance data were attributed to the anode and cathode overpotentials, respectively. (C) 2004 Elsevier B.V All rights reserved.