The catalytic activity of copper, manganese, and copper-manganese oxide catalysts with respect to NO reduction with CO has been investigated in the temperature range 25-300 degreesC. Copper-manganese oxide catalysts with Cu:Mn ratios of 1:2 and 1:1 where the two metals form spinel-like phases have shown the highest activity. With the three kinds of catalysts NO reduction proceeds to NZ formation over the whole temperature range. The texture changes of the support after heat treatment and the adsorption characteristics of all samples have been evaluated by means of adsorption studies. Chemical and X-ray phase analyses and EPR investigations have been performed.