Porous carbon nanofibers were prepared through electrospinning a blend solution of polyacrylonitrile and poly(L-lactide), followed by carbonization at different temperatures and in different atmospheres. Structural features of these porous carbon nanofibers were characterized using scanning electron microscopy, transmission electron microscopy, thermogravimetric analysis, X-ray powder diffraction, and Raman spectroscopy. Surface area and pore structure were evaluated using the nitrogen adsorption technique. It was found that carbon fibers prepared by this scalable and relatively economical method exhibited a porous surface morphology with high specific surface area and large pore volume. The fiber diameter, surface area, pore volume, bulky crystalline structure, and surface crystalline structure of these carbon nanofibers showed a strong dependence on the polymer precursor composition and carbonization condition. (C) 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 47: 493-503, 2009