Tungstated TiO2 (WTi), tungstated Fe2O3 (WFe), tungstated SnO2 (WSn), sulfated TiO2 (STi), sulfated Fe2O3 (SFe), and sulfated SnO2 (SSn) are used as the support for the In and Pd catalysts for the SCR of NO with methane. It was found that the In/STi catalyst with a 2% indium loading showed the highest NOx conversion (39% at 450 degrees C and 12,000 h(-1)) among all of the catalysts studied. The acid strength of the STi support was very important for the formation of the InO+ site, which was thought to be the active site for NO reduction. The activity of the In/STi catalyst can be improved by increasing the surface area of the STi support. The most attractive feature of the In/STi catalyst is its high resistance for SO2.