Electroosmosis experiments through a Nafion membrane have been per-formed using methanol-water KCl solutions in different experimental situations. The influence on the electroosmotic transport of the percentage of methanol on solvent at different electrolyte concentrations has been studied. The experimental results show that the presence of methanol on the solutions affects strongly to the electroosmotic flow. From the current-voltage curves determined for this membrane system, the limiting currents were obtained at different volume percentages of methanol. The values obtained decrease with increasing the percentage of methanol and a minimum value seems to be reached at certain percentage of alcohol. (C) 2004 Elsevier B.V. All rights reserved.