Lignin-based electrospun nanofibers (eNFs) were prepared and thermally stabilized at 250 degrees C and subsequently carbonized at 1400 degrees C. The starting blend was prepared in dimethyl formamide (DMF) solution with lignin and polyacrylonitrile (PAN), while a lignin-grafted-PAN (L-g-PAN) copolymer served as compatibilizer. The viscosity was highest of the DMF solution with PAN, and decreased for the lignin/PAN blends and additionally in presence of L-g-PAN. The uniform eNFs with clean surfaces dispose of diameters between 400 nm and 1 mu m. The average diameter of eNFs decreased by the thermal treatment and at higher lignin contents in the blends. Remarkable shrinkage by carbonization was observed in all nanofibers. The successful carbonization of all electrospun carbon nanofibers (eCNFs) was confirmed by Fourier transform-infrared (FT-IR) spectroscopy. The specific tensile strength and elastic modulus of the eCNF mats from lignin/PAN blends were improved by the addition of L-g-PAN, and it can be safely concluded that it acts as a compatibilizer between lignin and PAN.