A miniaturized poly(dimethylsiloxane) (PDMS)-based methanol steam reformer having a serpentine microchannel for application in a proton exchange membrane fuel cell (PEMFC) has been developed. The fabricated PDMS microreformer consists of four layers, and a commercial thin-flexible heater for reforming reaction is embedded in the PDMS layers. The volume of a PDMS microreformer is about 10 cm(3). The commercial Cu/ZnO/Al(2)O(3) reforming catalyst was used and the Cu/ZnO/Al(2)O(3) reforming catalyst particles of mean diameter 50-70 mu m was packed into the microchannels by fluidized method. In this study, the miniaturized PDMS microreformer was operated successfully in the operating temperatures of 180-240 degrees C and 30-40% molar methanol conversion was achieved in the temperature range for the feed rate of 10 and 50 mu l min(-1). (C) 2008 International Association for Hydrogen Energy. Published by Elsevier Ltd. All rights reserved.