Twenty-eight tibial fractures, initially treated with nonreamed interlocking nails, were exchanged to reamed intramedullary nails to promote union. Initially, there were 8 closed fractures with compartment syndromes; 5 Type 2 open fractures; 6 Type 3 A injuries; and 6 Type 3B injuries. Exchange nailing was performed if followup radiographs did not show callus formation between 3 and 5 months after injury. Originally, 16 of the 28 nailings were statistically locked. Twenty-five of 27 fractures united after exchange nailing. In 2 patients with bone loss, additional bone grafting was required. Infection developed in 3 patients after exchange nailing (11%). Exchange nailing is a useful method to promote union of tibial fractures when slow consolidation occurs after initial treatment with a nonreamed nail. This method should be combined with autogenous bone grafting in patients with bone loss. The procedure is safe and effective in closed and minor open fractures; however, caution should be exercised in patients with prior Grade 3B open fractures because of the risk of infection.