Silicon nitride nanofibers were prepared by direct nitridation of silicon powder, with an iron catalyst, under nitrogen flow. The as-prepared nanofibers have the α-Si3N4 structure. Micromorphology and phase composition of the as-prepared α-Si3N4 nanofibers were characterized by scanning and transmission electron microscopy and by X-ray diffraction analysis, respectively. The electronic structure of silicon nitride nanofibers was compared with that of Si3N4 powder by X-ray photoelectron spectroscopy and X-ray emission spectroscopy.