The membrane electrode assembly (MEA) studied was constituted with a gas diffusion electrode (E-TEK) impregnated with Nafion(R) solution which was assembled with a Nafion(R) 117 cation exchange membrane under heat and pressure. The MEA was used as anode in a membrane electrolysis (ME) cell with the objective to regenerate HCl and NaOH from NaCl. Current efficiency for hydrogen oxidation was determined and its value is 100%, which indicates that the only reaction occurring at the anode is the oxidation of hydrogen. Current-potential curves, recorded in different conditions, showed a linear variation in the range 0-3000 A m(-2) when hydrochloric acid concentration is below 2 mol dm(-3). In this case, the overvoltage was shown to be mainly due to the ohmic drop in the membrane and in the layer where Nafion(R) impregnation was performed. MEA overvoltage necessary to reach 3000 A m(-2) current density was about 0.12 V. For high HCl concentration (6-8 mol dm(-3)), the MEA overvoltage increased sharply with current density due to the adsorption of chloride anions on platinum catalyst. (C) 2005 Elsevier Ltd. All rights reserved.