PURPOSE: It is to evaluate and discuss the result of severe open tibial shaft fractures treated by Ilizarov external fixation. MATERIALS and METHODS: From the January 1992 to July 1997, 34 cases of severe open tibial shaft fracture in adults were treated with Ilizarov external fixator. 20 males and 14 females were followed for at least 1 year. RESULTS: Fractures were evenly distributed through proximal 1/3 to distal 1/3 and its pattern was mostly comminuted one. According to Gustilo-Anderson classification, it mainly consisted of type IIIa &IIIb(28 cases: 82%). Mean bony union time was 40.2 months. There were 5 cases(15%) of delayed union, 2 cases(6%) of nonunion, 5 cases(15%) of deep infection including 3 cases(9%) of osteomyelitis, 10 cases(29%) of pin tract infection, 4 cases(12%) of malunion and 11 cases(32%) of ankle stiffness. CONCLUSION: Conclusively, in the first place, for the successful treatment with Ilizarov external fixator, determining appropriate indications is the most important. Secondly, active reconstruction of soft tissue environment and early prophylactic bone graft, if necessary, are also essential to shorten union time. Thirdly, meticulous care of pin site and ankle motion is needed for the prevention of the two most common complications even though they are considered to be minor.