Selective reduction of nitric oxide by ammonia over sulfated CuO/gamma-Al2O3 was carried out in a fixed-bed reactor. The optimum temperatures of the fresh and sulfated CuO/gamma-Al2O3 in the selective catalytic reduction of NO are found to be 350 and 450 degrees C, respectively. NO reduction with the sulfated catalyst is somewhat higher than that of the fresh catalyst. The amount of N2O formation over the fresh and bulk sulfated catalysts is below 10% of NO in the feed stream. The intermediate in NO reduction by NH3 over the bulk sulfated catalyst is found to be ammonium sulfate from IR study. The activation energies of the fresh, surface, and bulk sulfated catalysts are found to be 29.4, 76.6, and 76.3 kJ/mol, respectively.