To study the effect of internal pressure distribution on the performance of a PEM fuel cell, a pressurized endplate was designed and fabricated. The endplate had a built-in hydraulically pressurized pocket with a thin wall facing the fuel cell assembly. Pressure sensitive films were used to measure the pressure distribution for both conventional and newly designed end plates. Fuel cell performance tests were conducted under selected conditions. It was found that the pressure distribution for the newly designed endplates was more uniform than for the conventional end plates, and an improved fuel cell performance was obtained with the newly designed end plates as well. (C) 2007 Elsevier B.V. All rights reserved.