The effect of Pt loading in the self-humidifying polymer electrolyte membrane (PEM) for polymer electrolyte membrane fuel cell (PEMFC) on the water uptake was investigated. The self-humidifying membrane was composed of two membranes made of perfluorosulfonylfluoride copolymer resin and fine Pt particles lying between them coated by a sputtering method. The membrane electrode assembly (MEA) was made using the decal method. The optimum amount of Pt particles embedded in the membrane for the self-humidification PEMFC was determined to be about 0.15 mg/cm(2), based upon the measurements of single cell performance characteristics and resistance. (C) 2003 Elsevier Science B.V. All rights reserved.