A three dimensional model of a proton exchange membrane fuel cell (PEMFC) operating with a polybenzimidazole (PBI) membrane is presented. This model is an improvement on the previous three models developed for this type of PEM fuel cell. The model accounts for all transport and polarization phenomena, and the results compare well with published experimental data for the same sets of operating conditions. The model predicts the oxygen depletion, which occurs in the catalyst area under the ribs, and a temperature rise of up to 20 K at a power density of 1000 W m(-2) can be expected depending on operating conditions. (c) 2006 Elsevier B.V. All rights reserved.