A model for the kinetics of NO reduction by CO on Rh(1 11) surfaces is proposed that takes into account recent experimental observations 94 on the formation of an N-NO intermediate as an alternative pathway to produce N-2, the formation of N-islands in the adsorbed phase, an increase of the NO dissociation probability with the number of neighboring vacant sites, and the blocking of NO dissociation due to the presence of neighboring co-adsorbed NO and CO species. When all these characteristics are taken into account, the overall behavior of the system in steady-state conditions, calculated through Monte Carlo simulations, is consistent with experimental observations. The effect and importance of each elementary process in the reaction kinetics is discussed. (C) 2004 Elsevier B.V. All rights reserved.