Fifty open fractures of the tibial shaft that were treated with débridement and interlocking nailing without reaming were followed for an average of twelve months. Most of the fractures were the result of high-energy trauma, and 68 per cent of the fracture wounds were grade III. Forty-eight (96 per cent) of the fifty fractures united at an average of seven months; there were no malunions. There were four infections (8 per cent), all at the sites of grade-III fractures. Locking screws broke in five tibiae (10 per cent), but the breakage did not result in a loss of reduction. Three nails broke, two at the sites of ununited fractures and one at the site of a healed fracture. These results are comparable with, or better than, those obtained with other forms of fixation, including immobilization with a cast, unlocked intramedullary nailing, and external fixation.