All tibial shaft fractures treated at one hospital during a five-year period were studied in a prospective trial. Ninety-one displaced fractures in adults were treated using a conservative policy that included early bone grafting when indicated. Sound bony union was obtained in all cases. Those that healed primarily took on average 16.3 weeks whereas the 24 per cent that required bone grafts took 35.1 weeks. The number of complications, most of which were minor, was considered acceptable. It is concluded that provided early bone grafting is performed when necessary, a basically conservative policy of treatment is satisfactory; bony union of all displaced tibial fractures is achieved in a reasonable period of time.