PURPOSE: To evaluate the clinical and radiological results of the treatment of mid-shaft clavicular nonunions using intramedullary fixation with threaded Steinmann pin and bone grafting. MATERIAL AND METHODS: In 16 patients treated with intramedullary fixation of threaded Steinmann pin and autogenous iliac bone grafting for the mid-shaft clavicular nonunions, 10 patients with follow-up over 1 year were investigated. All patients (10 clavicle fractures) underwent conservative treatment initially. The average age of patients was 56 years old (range, 18~70 years old). Eight cases were atrophic nonunions, two hypertrophic. A clinical assessment was evaluated postoperatively after 5 months according to the evaluation method of Kona et al. RESULTS: According to the evaluation method of Kona et al, four cases achieved excellent results, five cases good, and one case achieved a fair result. The average period until bony union was 9 weeks (range, 7~12.5 weeks) without infection, pin migration or breakage. One case showed skin irritation by lateral margin of Steinmann pin, which was subsided by pin removal after bony union. CONCLUSION: We obtained satisfactory results and have concluded that intramedullary fixation with threaded Steinmann pin and bone grafting could appropriately treat nonunions of the mid-clavicular fracture occurred after conservative treatment, because it minimizes soft tissue injury, gets relatively stable fixation and early ROM, predicts early bone union, facilitates pin removal under local anesthesia.