To elucidate the nerve, especially motor nerve, regeneration after interfascicular grafting, the method most often used clinically, the nerve grafting was performed on 40 adult rabbits. By resecting 2.0 cm of the right peroneal nerve, the sural nerve was made into 4 interfascicular grafts under a operating microscope. The cross section area of the grafts was about the same as that of peroneal nerve. Histological and evoked electromyographic observations were conducted on the maturation of regenerating nerves of up to 24 post-operative months, when the maturation would have been completed. The present histological and evoked electromyographic observations revealed that about 70% of nerve, especially motor nerve, recovery was attained after interfascicular grafts as compared with normal nerve. In the nerve regeneration after interfascicular grafts, several factors differing from the case of suture are involved, and these factors were considered from the experimental findings.