The ability of electrocoagulation to remove Cr(III) from aqueous solutions is studied using aluminium anode and taking into account many factors such as pH, potential, time and temperature. In order to check these factors and their effects on the electrocoagulation of Cr(III), we have established a model of this technique following a methodological strategy using experiments design. The mathematical model is established. using a central composite design rotatable and uniform. The model describes the change of the measured responses of chromium removal efficiency. energy consumption and aluminium dissolved according to the pH, potential, time and temperature. The graphical representation of this model in the space of the variables enabled us to define the optimum conditions for these parameters. The optimum value of pH, potential, time and temperature are respectively 4.23, 9.14 V, 10 min. and 27.5 degrees C. An efficiency of 91% of the removal chromium is observed with an energy consumption of 3.536 kWh/m(3). (c) 2008 Elsevier B.V. All rights reserved.