Objective: Studies showed elastic stable intramedullary nailing (ESIN) of displaced midclavicular fractures has excellent outcomes, as well as high complication rates and specific problems. The aim was to discuss ESIN of midshaft clavicular fractures.Methods: Totally 60 eligible patients (aged 18-63 years) were randomized to either ESIN group or non-operative group between January 2007 and May 2008. Clavicular shortening was measured after trauma and osseous consolidation.Radiographic union and complications were assessed. Function analysis including Constant shoulder scores and disabilities of the arm, shoulder and hand (DASH) scores were performed after a 15-month follow-up.Results: ESIN led to a signifcantly shorter time to union, especially for simple fractures. In ESIN group, all patients got fracture union, of which 5 cases had medial skin irritation and 1 patient needed revision surgery because of implant failure. In the nonoperative group, there were 3 nonunion cases and 2 symptomatic malunions developed requiring corrective osteotomy. At 15 months after intramedullary stabilization, patients in the ESIN group were more satisfied with the appearance of the shoulder and overall outcome, and they benefited a lot from the great improvement of post-traumatic clavicular shortening. Furthermore,DASH scores were lower and Constant scores were significantly higher in contrast to the non-operative group.Conclusion: ESIN is a safe minimally invasive surgical technique with lower complication rate, faster return to daily activities, excellent cosmetic and better functional results,restoration of clavicular length for treating mid-shaft clavicular fractures, resulting in high overall satisfaction, which can be regard as an alternative to plate fixation or nonoperative treatment of mid-shaft clavicular fractures.