BACKGROUND The articles that have reported on the size at which a segmental defect of clavicular non-union requires bone grafting are scarce. This study evaluated the functional and radiologic results of fixation by locking compression plate (LCP) without bone graft when the defect size is less than 2 cm following bone sclerosis removal for the treatment of clavicular non-union. METHODS The study included 17 patients with mid-shaft clavicular non-union. All patients underwent bone sclerosis resection and fixation using LCP without bone graft. The patients were evaluated preoperatively, and after a minimum of 24 months (mean, 44.47 months; range, 24 to 60 months) postoperatively in terms of the disabilities of the arm, shoulder and hand (DASH) score, the Constant-Murley score, and radiography. RESULTS In this study, no patients were lost to follow-up. The mean DASH score improved from 38.76 ± 7.76 (31.00-46.52) points preoperatively to 19.88 ± 7.18 (12.70-27.06) points 2 years postoperatively (P < 0.01). The mean Constant-Murley score improved from 41.59 ± 8.81 (32.78-50.40) points preoperatively to 75.47 ± 13.50 (61.97-88.97) points 2 years postoperatively (P < 0.01). Radiographs revealed fracture union in all patients. No correlations between the defect size and the postoperative Constant-Murley score or between the defect size and the postoperative DASH score were found based on Pearson tests. No complications, particularly acromioclavicular joint complications and sternoclavicular joint complications, were observed. CONCLUSIONS In conclusion, we can suggest, from the findings of our study, that bone sclerosis resection and fixation using LCP without bone graft is effective for the treatment of clavicular non-union involving a gap of less than 2 cm and has a low rate of complications.