A study is reported on the oscillatory effects observed in the oxidation of carbonmonoxide/propene mixtures over a supported platinum catalysts in a flow reactor. The oscillatory behaviour has been examined over a range of operating variables, together with catalyst site concentration. It is shown that the elementary step treatment developed for explaining the behaviour of CO/butene oxidation provides a largely satisfactory approach for this system also. The kinetic model accounts for the appearance and disappearance of oscillations as the reactor residence time is increased. A simpler asymptotic third-order model, soluble analytically, is useful in that it successfully predicts the appearance of the oscillations. For the reaction dynamics observed, it is not necessary to invoke temperature effects or the formation of surface oxides.