Electron-transfer kinetics for the reduction of non-heme oxoiron(IV) complexes by a series of ferrocene derivatives were examined in deaerated acetonitrile, and the resulting data were evaluated in light of the Marcus theory of electron transfer to determine the reorganization energies of electron transfer and the one-electron reduction potentials of non-heme oxoiron(IV) complexes. The electron-transfer properties of non-heme oxoiron(IV) complexes are featured by the larger reorganization energies of electron transfer and the lower one-electron reduction potentials as compared with those of heme oxoiron(IV) complexes.