In chemical looping with oxygen uncoupling (CLOU), the fuel reacts with gaseous oxygen released by the oxygen carrier at suitable temperatures and oxygen partial pressures, unlike the CLC, where only the lattice oxygen reacts with the fuel. As a CLOU oxygen carrier, bi-metallic Cu-Mn oxide demonstrates high combustion efficiency for solid and gaseous fuels. However, the effects of pollutant species, such as nitrogen oxide (NO), on its performance are not well-understood. The purpose of this study is to investigate how NO interacts with a Cu-Mn oxide oxygen carrier during CH4 combustion in the CLOU process. The oxygen carrier was reduced via CH4-N2 gas mixture with and without NO in a batch-fluidized bed reactor. The results show that the adverse effect of NO on CH4 conversion is small and it becomes less pronounced as the temperature increases. On the other hand, NO can interact with both the oxidized and reduced oxygen carrier particles and the full reduction of the oxygen carrier takes slightly longer in the presence of NO. With an oxidized oxygen carrier (CuMn2O4), a small amount of NO oxidizes to NO2 in the absence of CH4 as a result of the interaction with the oxygen carrier. However, in the presence of CH4 during a complete reduction cycle, NO and total NOx (NO+NO2) concentrations decrease and ultimately reach zero, indicating NO reduction to N2 on the reduced oxygen carrier (Cu and MnO) while oxidizing the oxygen carrier.