In this paper, a comprehensive exergoeconomic analysis of a 10 kW PEM fuel cell at various operating temperatures, pressures, cell voltages and air stoichiometries is performed. The analysis is performed at fuel cell operating temperatures (T/T-0) and pressures (P/P-0) ranging from 1 to 1.25 and 1 to 3, respectively. In addition, the calculations are performed on typical fuel cell operating voltages of 0.5 V and 0.6 V and at air stoichiometries of 2, 3 and 4 in order to determine their effects on the exergy cost of the fuel cell. The calculated results demonstrated the significance of the operating pressure, cell voltage and air stoichiometry on the exergy cost of the fuel cell. Furthermore, lower capital cost of the fuel cell. annual O & M cost and hydrogen cost could contribute to a drastic reduction in the exergy cost. Thus. a substantial improvement in the overall results could be achieved. (C) 2004 Elsevier Ltd. All rights reserved.