Ten millimeter gaps in sciatic nerves of rats were repaired by vein grafting (n = 30) and by nerve grafting (n = 30). Electrophysiologic evaluation demonstrated that the nerve-graft group had a significantly higher percentage of re-innervation and shorter delay of terminal latency in myoelectrical response evoked by electrical stimulation of the sciatic nerve, compared with the vein-graft group at two and three months. But there were no differences between the two grafted groups after six months. In both grafted groups, the numbers of myelinated nerve fibers increased substantially over time, although the vein-grafted segments had smaller numbers of fibers than the nerve-grafted segments at both three and 12 months. Microangio-grams also demonstrated different patterns of revascularization between the two groups. Results suggest that, although autologous vein grafting requires a longer period of time for nerve regeneration, compared with autologous nerve grafting, its ability to repair nerve is considerable.