The effect of the iron distribution in steam-activated FeZSM-5 and Fe-silicalite on their catalytic performance for direct N 2 O decomposition and for the oxidative dehydrogenation of propane (ODHP) with N 2 O and O 2 was investigated by means of steady-state and transient pulse experiments. Steam-activated FeZSM-5, containing a large fraction of iron as oligonuclear Fe x O y clusters, is more active and selective in ODHP and direct N 2 O decomposition than steam-activated Fe-silicalite, where isolated iron species predominate. This suggests that the same type of iron centers is involved in both conversions. The higher activity of steam-activated FeZSM-5 is associated to the higher mobility of atomic oxygen species attached to oligonuclear iron species, which lead to a faster oxygen desorption in direct N 2 O decomposition as well as to a faster transfer to propane in the ODHP reaction. Steam-activated FeMFI zeolites were found to be highly effective catalysts for ODHP with N 2 O, with initial propene yields up to 24%. Relatively high yields of propionaldehyde are also obtained, which mainly originates from the selective oxidation of propene. The unique ODHP performance of iron zeolites requires the use of N 2 O as monooxygen donor. Such species cannot be created by O 2 . Only a fraction of oxygen species deposited over iron sites of FeMFI upon N 2 O activation was found to be active towards propane oxidation under transient vacuum conditions. This is explained by a fast transformation of short-living highly reactive atomic oxygen species into less reactive ones.