Copper oxide supported on ZrO 2 catalysts (CuO x /ZrO 2 ) were prepared by impregnation of ZrO 2 with aqueous solutions of Cu(NO 3 ) 2 . Copper-sulphated zirconia catalysts were prepared by three different methods: (i) impregnation of ZrO 2 with aqueous solutions of CuSO 4 , (ii) impregnation of sulphated-ZrO 2 (SZ) with toluene solutions of Cu(acetylacetonate) 2 , and (iii) sulphation of CuO x /ZrO 2 via the gas-phase. Samples were characterized by X-ray diffraction (XRD), UV-VIS diffuse reflectance (DRS), Fourier transformed infrared (FT-IR), and redox cycles with CO and O 2 . The reduction of NO with C 3 H 6 in the presence of excess O 2 was studied in a flow apparatus fed by a reactant mixture of NO:C 3 H 6 :O 2 =4000:2000:20,000ppm in He.Irrespective of the preparation method (i) catalysts with the same sulphate content had the same covalent sulphates, and (ii) catalysts with the same copper content and with the same sulphate content were equally active and selective. Sulphated samples were far more selective than the correspondent unsulphated CuO x /ZrO 2 , particularly sulphated samples with higher copper content. The presence of sulphates (i) made Cu(II) less reducible than in CuO x /ZrO 2 and (ii) prevented CuO segregation. The catalytic activity and selectivity of copper-sulphated catalysts depends on a cooperative effect of copper and sulphate. The role of copper is to determine the activity for the NO reduction, and that of sulphate to maintain high the selectivity.