The Auger spectra of the iron oxides have been investigated. The relative amplitudes of the Auger lines from oxygen and iron have been determined for FeO, Fe3O4, α-Fe2O3, γ-Fe2O3, and FeOOH. It was found that the amplitude ratio s of the O (510 eV)/Fe (703 eV) lines was, to a first approximation, directly proportional to the ratio of oxygen and iron in the chemical formula. Structure was observed in the spectra resulting from the Fe M2,3 VV transition. Different spectra were observed for Fe, FeO, Fe3O4, Fe3O3, and FeOOH; however, the same spectra were obtained for α- and γ-Fe2O3.