Management of compound fractures of the tibial diaphysis forms a large proportion of the trauma workload at Tygerberg Hospital. This prompted a prospective study to compare external fixation with unreamed intramedullary nailing in the treatment of grade-I, II, IIIA and IIIB compound fractures of the tibial diaphysis. For a year we followed up 18 skeletally mature patients. External fixation was used in eight patients, four of whom had grade II fractures, two grade IIIA and two grade IIIB. Ten fractures (two grade-I, one grade-II, two grade IIIA and five grade IIIA) were stabilised with an unreamed intramedullary nail. Except for the method of fixation, fracture care was the same: all patients received antibiotics on admission, primary fracture debridement occurred within 24 hours and redebridement within 48 to 72 hours of injury. Definitive fixation by external fixator or intramedullary nailing, with wound closure, skin graft and/or myofasciocutaneous flapping was done within a week of injury. We assessed rates of infection, hardware failure, mal-union, additional procedures, hospital stay and time to union. There were no cases of wound infection in either group, but a progression of fracture gap in one patient treated by intramedullary nailing may suggest sub-clinical infection. All patients treated with external fixators developed pin-tract infection, and in five patients the external fixator had to be removed before union. One external fixator pin failed and was re-inserted under anaesthetic. There were two intramedullary nail locking screw failures, but they required no intervention. Additional procedures required in the group treated by external fixator far outnumbered those needed in the intramedullary nailing group. Fracture alignment appeared more anatomical in the patients treated by intramedullary nailing. We found no significant difference in healing rates or length of hospital stay. Our results suggest that intramedullary nailing is the more efficient method of fracture stabilisation.