Kinetics of the simultaneous reduction N2O and NO by CO on CUCo2O4 has been studied. The reactants are adsorbed onto the coordination-unsaturated cations of the catalyst. The studies showed that the reactions of N2O and CO and of NO and CO occur between the adsorbed reactants on the catalyst surface; the catalyst surface is partially reduced during both these reactions. It was found that NO inhibits the reaction between N2O and CO, because N2O and NO compete for the active surface sites. The adsorption capacity of the catalyst is significantly higher for NO than for N2O and hence NO displaces N(2)Oads from the surface. The inhibition occurs on strongly localized sites and does not affect on the behaviour of the remaining free sites. At such blockage, the N2O reduction rate decreases in direct proportion to the amount of adsorbed NO.