This study explores the ability of nickel catalysts supported over Mg-Al mixed oxides (Ni/HT) by incipient wetness impregnation technique for the catalytic wet air oxidation of aqueous crystal violet solutions. The effect of operational conditions such as temperature, pressure, pH, presence of the catalyst and initial dye concentration has been tested. It has been demonstrated that Ni/HT is an efficient catalyst for the CWAO of crystal violet (CV) at mild reaction conditions. The reaction which was carried out at its natural pH, showed to be the most efficient when Ni/HT was employed. The catalyst does not lose any of its activity in the recycling experiments performed, when CV degradation is considered. (C) 2011 Elsevier B.V. All rights reserved.