Different mechanisms have been proposed in the literature for the selective catalytic reduction of NO by hydrocarbons (and in particular by propane and propylene) over supported PT catalysts. This manuscript reviews the available experimental evidence in support of a scheme involving the initial partial oxidation of the hydrocarbon an the subsequent formation of a surface cyanide or isocyanate intermediate. Furthermore, we present results of reaction kinetics analyses which indicate that such a reaction scheme can describe the available kinetic data at a quantitative level.