The structural, electric and magnetic properties of (100)-oriented Fe O /NiO and Fe O /CoO superlattices on MgO(100) have been studied. The films were prepared by an activated reactive evaporation method. The lattice constants of each layers were a little changed from the bulk values due to a lattice mismatch with the substrate. The Fe 2p XPS of both Fe O /NiO and Fe O /CoO interfaces suggested the formation of stoichiometric Fe O . The saturation magnetizations (Ms) of Fe O /MO superlattices were compared with that of a Fe O thin film as a function of the thickness of MO layers. The reduction in Ms of Fe O /NiO could be linked with the large exchange coupling with NiO. While the increase in Ms of Fe O /CoO was probably caused by the ferromagnetic coupling of the CoO interface with the Fe O layer. 3 4 3 4 3 4 3 4 3 4 3 4 3 4 3 4 3 4 3 4