Carrier transport across Fe3 O4 Si interfaces has been studied for two different Si substrate orientations. The Fe3 O4 films exhibit a (111) texture on both (111)- and (001)-oriented substrates and field-cooling experiments show the characteristic step in film magnetization at the Verwey transition temperature of magnetite. Current-voltage measurements indicate the formation of high-quality Schottky barriers with an ideality factor of about n=1.06. Fits to the transport data using the thermionic emission/diffusion model yield Schottky barrier heights of 0.52 and 0.65 eV for Fe3 O4 Si (111) and Fe3 O4 Si (001) structures, respectively. The interface between the magnetite films and silicon substrates consists of a crystalline iron silicide/amorphous oxide bilayer with reduced magnetic moment.