CuO/gamma-Al2O3 is confirmed as the most active catalyst among eight gamma-Al2O3-supported single metal oxides for the destructive oxidation of (CH3)(2)S-2. To investigate the promoting effect, nine different metal oxides were separately added to CuO/gamma-Al(2)O3. The experiments reveal MoO3 as the most effective promoter and the optimal added amount as around 10 wt%. Thermograms of TPR and spectra of XRD, employed to characterize the surface properties of a CuO-MoO3/gamma-Al2O3 catalyst, verify that the addition of molybdenum oxide inhibits the growth of copper oxide crystal but may cause the formation of Cu3Mo2O9 and CuMoO4 phases. A CuO-MoO3/gamma-Al2O3 catalyst exhibits higher activity and improved resistance to deactivation by sulfur compounds than does a commercial platinum catalyst. Since CH3SH may be easily converted into (CH3)(2)S-2, the above-mentioned catalysts are decidedly effective in treating waste gas containing CH3SH.