A series of 33 cases of Grade II and III open tibia fractures were treated with local wound care followed by application of the A-O external fixator. Two transfixing Steinmann pins were usually used above and two below the fracture site. In six cases one Steinmann pin and one anteroposterior Schanz half pin above and below the fracture were combined with a triangulated frame. Additionally, minimal internal fixation with lag screws was used in five cases.Union was achieved in 83% of tibiae in an average time of 9.9 months. Union occurred faster when the fixator was removed in less than 3.5 months but then the incidence of malunion tended to rise. Three patients required early amputation. Eleven tibiae developed deep wound infections. Knee function was well preserved but ankle function was often impaired.The A-O fixator performed as a useful, simple, stable, light weight and versatile system in the care of these Grade II and III fractures. However, many problems intrinsic to the open tibia fracture remain.