In this work, removal of arsenic by electrocoagulation with iron and aluminium electrodes is studied in a batch bench scale plant. Results demonstrate that both iron and aluminium electrocoagulations are a robust technology capable of removing arsenic down to 10 mu g dm(-3) (the level fixed by most environmental and health agencies). Nevertheless, aluminium electrocoagulation is not as efficient as iron, one for the removal of arsenic when current densities below 2 mA cm(-2) are applied. The effect of the current density (from 0.1 to 4.0 mA cm(-2)) is studied with both electrodes. Results show that this parameter influences slightly on the range of pH in which the process works (7-9) and also on the efficiency (always over 99.9%), but it is not a limiting parameter. Results can be easily explained taking into account the solubility of iron, aluminium and arsenates species present in the treated water. (C) 2011 Elsevier B.V. All rights reserved.