Direct (oxidation) methanol fuel cells (DMFCs) are attractive for several applications, however, there are several barriers which must be overcome before they can become an alternative to internal combustion engines. At present, methanol crossover from the anode to the cathode appears to be the major Limitation. This work shows the information on the influence of methanol crossover in DMFC and on the effort to get a more methanol-impermeably polymer electrolyte found in the literature.