Carbon-based nanofibers can be used as anode materials for lithium-ion batteries. Both pure carbon nanofiber and C/Fe3O4 composite nanofibers were prepared by electrospinning and subsequent carbonization processes. The composition and structures were characterized by Fourier transformation infrared spectroscopy, X-ray diffraction, scanning and transmission electron microscopy. The electrochemical properties were evaluated in coin-type cells versus metallic lithium. It is found that after an annealing temperature of 500-700 degrees C, the carbon has disordered structure while Fe3O4 is nanocrystalline with a particle size from 8.5 to 52 nm. Compared with the pure carbon nanofiber, the 600 degrees C-carbonized C/Fe3O4 composite nanofiber exhibits much better electrochemical performance with a high reversible capacity of 1007 mAh g(-1) at the 80th cycle and excellent rate capability. A beneficial powderization phenomenon is discovered during the electrochemical cycling. This study suggests that the optimized C/Fe3O4 composite nanofiber is a promising anode material for high performance lithium-ion batteries. (C) 2008 Elsevier B.V. All rights reserved.