In this work, a three-dimensional model of a phosphoric acid fuel cell (PAFC) has been developed and has been applied to investigate the effects of process parameters on the fuel cell performance. Simulation results show good agreement with experimental data found in the literature. The model accounts for the local distribution of the concentration of reactant and product gases in the anode and cathode flow regions and the electrical potential distribution on the surface of the cathode electrode, in several cases of different utilization of the reactant gases and different values of current density. The developed model predicts with satisfactory accuracy the average cell and stack voltage and also the generated power. (c) 2006 Elsevier Ltd. All rights reserved.