Proton exchange membrane fuel cells (PEMFC) operating with Nafion(D membranes have encountered numerous problems associated with water management and CO poisoning because of their low temperature of operation. Alternative high temperature membranes have been investigated, one such membrane being polybenzimidazole (PBI). This paper presents a one dimensional mathematical model, which predicts the polarization performance of a PEMFC using a PBI membrane. Peak power densities in the same order as Nafion (R) are predicted. Results indicate that the greatest scope for improving PBI PEMFC performance is increasing the membrane conductivity and improving the catalyst performance as it interfaces with the PBI membrane. (c) 2005 Elsevier Ltd. All rights reserved.