Reamed intramedullary nailing was carried out on R57 Gustilo grade-IIIB tibial fractures in 55 patients. After debridement, there was substantial bone loss in 28 fractures (49%). The mean time to union was 43 weeks (14 to 94). When there was no bone loss, the mean time to union was 32 weeks; it was 45 weeks if there was bone loss. Fractures complicated by infection took a mean of 53 weeks to heal. Revision nailing was necessary in 13 fractures (23%) and bone grafting in 15 (26%). In ten fractures (17.5%) infection developed, in four within six weeks of injury and in six more than four months later. Of these, nine were treated successfully, but one patient required an amputation because of osteomyelitis. Our results indicate that reamed intramedullary nailing is a satisfactory treatment for Gustilo grade-III tibial fractures.