PURPOSE: To evaluate the clinical and radiological result of the treatment for the fracture of proximal humerus using intramedullary nail. MATERIALS AND METHODS: Nine cases with fractures around the shoulder joint treated with Polarus IM nail from February 1999 to June 2002 was selected. There were 1 case with segmental fracture, 2 cases with nonunion after conservative treatment, 3 cases with nonunion after IM nail, 1 case with nonunion after pinning, 1 case with metal failure after plate fixation, and 1 case with fracture combined with shoulder dislocation. Bone union was evaluated with simple radiographic findings, and functional evaluation was done using Kona evaluation method. RESULTS: The average follow up period after the operation was 16 months and the average duration of immobilization was 2 weeks. All cases showed radiographic union and the average duration until union was 3.1 months. On the functional evaluation using Kona evaluation method, 3 cases excellent, 3 cases good, 2 cases fair, and 1 case showed poor result. The cases with poor result had combined elbow, forearm, and hand fractures at the initial injury. The complication of periprosthetic fracture caused by repeated trauma was reported in 1 case. CONCLUSION: Polarus IM nailing can result in good clinical and functional results for the treatment of nonunion, plate failure, segmental fracture and fracture of proximal humerus with shoulder dislocation.