We have experienced five cases of intraoperative fracture of the tibia assoicated with removal of ACE interlocking tibial nail. All fractures occured in young patients whose ages ranged from eighteen to twenty-nine years(mean, 24 years). We think the main reason of the fracture was characteristic design of ACE nail such as prominent distal angulation and posterior longitudinal slot. The other factors were age of the patient, material of the nail and timing of removal of the nail. In conclusion, we advise caution in the removal of the ACE reamed interlocking intramedullary tibial nail in young patient.