We investigated the effects of the compositions of catalyst layers and diffusion layers on performances of the membrane electrode assemblies (MEAs) for direct dimethyl ether fuel cell. The performances of the MEAs with different thicknesses of Nafion membranes were compared in this work. The optimal compositions in the anode are: 20 wt% Nafion content and 3.6 mg cm(-2) Pt loading in the catalyst layer, and 30 wt%. PTFE content and 1 mg cm-2 carbon black loading in the diffusion layer. En the cathode, MEA with 20 wt% Nafion content in the catalyst layer and 30 wt% PTFE content in the diffusion layer presented the optimal performance. The MEA with Nafion 115 membrane displayed the highest maximum power density of 46 mW cm(-2) among the three MEAs with different Nafion membranes. Copyright (C) 2009 John Wiley & Sons, Ltd.