The catalytic activities of Fe-MFI (88% exchange) and Cu-MFI (122% exchange) zeolite catalysts for the decomposition and mainly the selective reduction of nitrous oxide by propene have been studied in the temperature range from 523 to 773 K. In the presence of oxygen and water vapor, both materials reveal strong retardation of their activity. When propene is added as reductant, Fe-MFI showed very high activity even in the low-temperature region and at low propene concentrations, whereas Cu-MFI is strongly deactivated.