Microsurgery offers a more effective approach to the brachial plexus lesions than any treatments previously available. The authors have performed operation to the injured plexus by microsurgical techniques since 1980. We selected 15 patients whom we could follow more than one year and had results as follow. 1. The causes of injuries were traffic accident(7 cases), gun-shot injury(4 cases), stab wound(3cases), and belt injury (1 case). 2. Two patients had preganglionic lesion and 13 patients had postganglionic lesions, among which seven cases were supraclavicular and six cases were infraclavicular. Most frequently injured site was in upper two roots and upper trunk (7 cases). 3. All of them were treated by surgical intervention, 12 cases by interfascicular nerve graft using autogenous sural nerve, one case by intercostal neurotization, one case by neurolysis, and one case by exploration only. 4. Elbow flexor and deltoideus were involved easily by injury than other muscles, but they had best prognosis to the microsurgical treatment. 5. The recovery of wrist and finger function was poor but they were frequently preserved from injury.