A novel structure of membrane electrode assembly (MEA) for a passive direct methanol fuel cell (DMFC) was proposed to achieve high performances. Composite membrane with low methanol cross-over and diffusion layers with hydrophilic nano-particles developed in this study were used for a novel MEA structure. The membrane and the diffusion layers were investigated for water back diffusion effects and performances in a passive DMFC. The proposed electrodes were proven to be two times more effective in water back diffusion than conventional electrodes, and their MEAs showed higher :performances than conventional MEA. The novel MEA with composite membrane showed power density of 48 mW cm(-2) at 0.3 V, which is 1.5 times higher than a conventional MEA with Nafion (R) membrane. (c) 2006 Published by Elsevier B.V.