Co–Na–MOR was prepared by ion-exchange of Na–MOR with an aqueous solution of cobalt acetate (Co–Na–MOR–9.2–104, Si/Al=9.2, and cobalt-exchange percentage=104). We studied the catalytic activity of this sample (i) for the SCR of N 2 O, (ii) for the SCR of NO, and (iii) for the simultaneous SCR of N 2 O and NO, where SCR stands for “Selective Catalytic Reduction with CH 4 in the presence of O 2 ”. Catalytic measurements were performed in a flow apparatus with GC analysis of reactants and products.Results show that Co–Na–MOR is active and selective (i) in the SCR of N 2 O, (ii) in the SCR of NO and (iii) in the simultaneous SCR of N 2 O and NO. The NO conversion in the simultaneous SCR of NO and N 2 O equalled that in the SCR of NO. Analogously, the N 2 O conversion in the simultaneous SCR of NO and N 2 O equalled that in the SCR of N 2 O. These findings strongly suggest that on Co–Na–MOR the simultaneous SCR of NO and N 2 O consists of two independent reactions: the SCR of NO, and the SCR of N 2 O.We conclude that Co–Na–MOR is a potential catalyst in the process causing the simultaneous SCR of N 2 O and NO, using CH 4 alone as the reducing agent, in the presence of excess O 2 .