Selective catalytic reduction of NO by propene has been investigated over noble metal (Pt, Pd, Rh)-based ZSM-5 catalysts. These samples were tested in a gas mixture system in the presence of excess oxygen, simulating lean-burn exhaust gases. The sequence in activity for NO reduction was Pt > Rh similar to Pd. Regarding the selectivity of the reaction to N-2, an opposite trend was observed: Rh > Pd similar to Pt. The catalytic systems have presented stable operation under isothermal conditions during time-on-stream experiments.