An experimental and theoretical study of the oxidation of methanol in the absence and in the presence of NO has been performed. The experiments were conducted in an isothermal quartz flow reactor at atmospheric pressure in the temperature range 700-1500 K. The influence of the temperature, oxygen concentration, and presence of NO on the concentrations of methanol, CO, CO2, and NO has been analyzed. A reaction mechanism based on the model of Glarborg et al.(1) for hydrocarbons/NO interactions, updated in relation to the methanol reaction subset has been used for calculations. The results show that the oxidation regime of methanol for different air excess conditions is very similar in the absence of NO, but significant differences are observed when NO is present. The presence of NO implies a different behavior depending on the stoichiometry, in the way that such presence results in a inhibition of methanol conversion for richest conditions, while it promotes; methanol oxidation for very lean conditions. The experimental results are analyzed in terms of detailed chemistry and the main issues are discussed.