The main objective of this work was to study the degradation of the methyl violet dye in aqueous solution using Fenton process. Effects of various experimental parameters of the oxidation reaction of the dye were investigated. The parameters studied were the initial pH, the temperature, the stirring velocity, and the initial concentrations of FeSO4, of H2O2 and of the methyl violet dye. Even the effect of FeSO4 as catalyst has been compared with those of other catalysts FeCl3 and Fe (NO3)(3). The optimum conditions had been determined, and it was found that efficiency of degradation obtained after 60 min of reaction, was about 97.6%. The optimal parameters were: initial pH = 3; [H2O2](0) = 2.1 mM; [Fe2+] = 0.06 mM; for a concentration of dye [MV](0) = 0.06 mM; temperature = 30 degrees C. The experimental results showed that the Fenton's reagent was effective for the degradation of methyl violet dye with a low concentration of H2O2 and Fe2+. (C) 2009 Elsevier B.V. All rights reserved.