The effect of H2S on the rates of toluene hydrogenation of sulfided Mo, Ni, Ni-Mo and Ni-Mo-P/alumina catalysts has been determined at 6 MPa, 350 degrees C over a large range of H2S partial pressure. In those conditions, Ni/alumina is nearly inactive. For the three other catalysts, similar trends are found with in particular no effect of H2S at high partial pressure. In the presence of NH3, the effect of H2S remains globally the same.