The catalytic reduction of NO to N-2 and CO2 by C over Cu/C was investigated and a relationship between the conversion of NO and Cu loading obtained. An optimum conversion of 100% was obtained at 410 degrees C over a Cu/C sample that contained 20 wt% Cu. For higher Cu contents the conversion decreased. The selectivities to N-2 and CO2 at 360 and 410 degrees C were 100% over the samples that contained 5-30 wt% Cu. As the reaction time increased; the conversion of NO first decreased and later increased. An explanation is provided for this behavior. H-2 titration was employed to determine; the change of the exposed surface area of Cu during reaction. The change of the surface area and of the pore size distribution of Cu/C during the reaction was also investigated.