PURPOSE: To evaluate of clinical results and malunion according to nail insertion site and early ambulation after unreamed interlocking intramedullary nailing for the treatment of tibial fractures, MATERIALS AND METHODS: We reviewed 46 tibial fractures that were treated with unreamed static intramedullary nailing prospectively from March 1997 to May 2001. Nail insertion site and angulation of fracture site were reviewed by radiograph. All of 46 cases, ambulation was started at postoperative 2 weeks, and then clinical outcomes were reveiwed RESULTS: In all 46 cases, union was achieved at average 18.2 weeks clinically and average 19.4 weeks radiographically. There is no significant difference in angulation according to nail insertion site, i,.e. after central/medial/lateral insertion, outcome was 2 . 4 5 degrees ±2 . 1 7 / 2 . 2 2 degrees ±1 . 8 4 / 1 . 7 3 degrees ±1.33(p; 0.705) in last follow up anterioposterior view, and 1.81 degrees ±1 . 1 3 / 2 . 6 7 degrees ±1 . 6 2 / 2 . 0 0 degrees ±1.64(p; 0.320) in last follow up lateral view. No breakage of intramedullary nails and no stiffness on adjacent joints. CONCLUSION: We confirmed that unreamed interlocking nailing in tibial fractures is one of the effective method for low recurrence of malunion and early ambulation