In a proton exchange membrane (PEM) methanol electrolyzer, the even supply of reactant to and the smooth removal of carbon dioxide from the anode are very important in order to achieve a high hydrogen production performance. An appropriate design of flow field and gas diffusion layer (GDL) is a key factor in satisfying the above requirements. Previous research has shown that hydrogen production performance of the PEM methanol electrolyzer cell was largely improved with a porous flow field made of sintered spherical metal powder compared with a conventional groove type flow field. Based on this improvement, the current study investigated the influence of polytetrafluoroethylene (PTFE) treatment of the anode GDL on hydrogen production performance of the PEM methanol electrolyzer with porous metal flow fields. Influences of operating conditions such as methanol concentration and cell temperature with the flow field were also investigated. Copyright (c) 2012, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.