OBJECTIVE: The purpose of this study is to determine the efficacy of reamed intramedullary nailing in the treatment of nonunions of the distal one-fourth of the tibia. Nonunions of the distal tibia are particularly difficult to treat given the short distal segment, the proximity to the ankle joint, and the fragile soft-tissue envelope. Intramedullary nailing is an attractive solution to this problem because it avoids extensive dissection, and the implant remains intraosseous, posing minimal problem for the soft tissues. DESIGN: Retrospective review of patient charts and radiographs. SETTING: Tertiary care orthopaedic hospital. PATIENTS/PARTICIPANTS: Thirty-two patients with nonunions of the distal one-fourth of the tibia. Prior treatments included casting, internal fixation with plates and screws, intramedullary nailing, and external fixation. Seven patients had a history of infection, but no patient had signs of active infection at the time of surgery. INTERVENTION: Study patients were treated by reamed, locked intra-medullary nailing. MAIN OUTCOME MEASUREMENTS: Main outcome measurements included time to union, correction of deformity, and complications including infection and reoperation. RESULTS: Average length of follow-up was 25 months (range 4-81 months). Twenty-nine out of 32 patients achieved union at an average of 3.5 months after reamed, locked intramedullary nailing. Of the remaining three, 2 patients united after dynamization (one at 4 months after dynamization and the other at 7 months), and the third patient united 4 months after exchange nailing. Deformity was corrected to a maximum of 4 degrees in all planes. Four patients had positive intraoperative cultures, and only 2 required removal of the nail after achieving union to control infection. There were no signs of chronic osteomyelitis in these 2 patients at the date of the last follow-up visit; 5.5 years and 2 years following nail removal. CONCLUSIONS: Reamed, locked intramedullary nailing is a reliable and safe procedure in the treatment of nonunions in the distal one-fourth of the tibia, even in the setting of prior infection or external fixation. It allows for excellent correction of deformity, which is an essential component of the procedure