The end-to-side neurorrhaphy was compared with pure end-to-end nerve graft in only few reports, although a number of studies have demonstrated that it is able to be an alternative method for the nerve gap. The purpose of this experiment was to evaluate the efficacy of the end-to-side neurorrhaphy, as comparing with that of conventional end-to-end nerve graft. Thirty Sprague-Dawley rats (250 to 300g) were divided into three groups of ten rats and all experimental procedures were done in the left hind limb. Group I served as non-grafted control. In Group II, the nerve branch to the gastroncnemius muscle was severed at 5mm below its bifurcation, and the distal ending of the nerve was sutured to the lateral side of the tibial nerve with epineural window. In Group III, the nerve branch to the gastroncnemius muscle was transected at two point, 5mm and 15mm respectively, distal to its bifurcation from tibial nerve, and then reanastomosed as like as a 10mm nerve graft. Five months later, all rats were subjected to nerve conduction velocity test and histologic examination, including the axon counts and the measurements of the diameter of muscle fibers. In Group II and III, nerve conduction velocity was slightly delayed and the recovery rates were 85.7% and 86.4%, respectively, compared to that of the Group I. But there was no statistically significant difference between each three groups. Mean values rate of the axon count in Group II and Group III were 50.8% and 95.5% respectively, compared to that of the Group I. There was a significant difference between Group I and Group II (p<0.001), and between Group II and III (p<0.0006). But there was no statistically significant difference between Group I and Group III. Average muscle fiber diameters in both Group II (44.22µm) and III (47.03µm) showed similar results each other, but less than that of Group I (54.25µm,p<0.003). In conclusion, the end-to-side neurorrhaphy may be used as an alternative choice for conventional end-to-end nerve graft in a certain extent of nerve gap.