The main problem in conventional direct methanol fuel cells (DMFC) is the methanol diffusion through Nafion membrane. In the present work, new composite membranes have been prepared from tin mordenite electrolyte and polymer binders, which have high protonic conductivity and better resistance against solvent uptake and methanol diffusion through the membrane. Tin mordenite electrolyte was reproducibly synthesized from H-mordenite and tin chloride in a larger scale (15 g) compared to that in previous work (5 g), and it exhibits stable and high protonic conductivity of 1 X 10(-2)S cm(-1) at room temperature and 100% relative humidity (RH). Tin mordenite based membranes (200 mu m thick) were prepared form ca. 60 wt% of tin mordenite and acrylic acid based polymer binders by screen printing, UV or EB cure processes. Homogeneous and flexible membranes with low methanol diffusion through the material can be obtained, which show reproducible and fair conductivity, e.g. 5 X 10(-4)S cm(-1) at 80 degrees C, 100% RH. Such membranes are promising for application in DMFC to replace Nafion.