A simplified kinetic model of the chemistry of NO reduction by the action of natural gas has been obtained. This model consists of 87 elementary reactions and 38 chemical species. It takes into account the natural gas decomposition and oxidation, the interaction between NO and hydrocarbons, and the conversion of the intermediate nitrogenous species. The concentrations of the species calculated with the model have been compared with those obtained experimentally using the operating conditions for which a good efficiency in the reburning zone is achieved. The comparison between the theoretical and experimental data of NO, HC,N, CO, and CO2 has been extended to the results obtained over a wide range of values of the operating conditions in the reburning zone.