Thirty three cases of the type III open tibial fractures treated by external fixation during last six years were analyzed. According to the classification of Gustilo, Mendoza and Williams, the fractures are subdivided into type IIIa, IIIb, IIIc. The fractures were follow up from 12 months to 58 months, average 32.7 months. The results were as follows;l. Among 33 cases, type IIIa fractures were 10 cases, type IIIb fractures were 18 cases and type IIIc fractures were 5 cases. 2. The average time for union was 36.5 weeks and the time for union was longest in IIIb fractures. Bone graft was done in 20 cases (60.6%). 3. Soft tissue defects were treated by split thickness skin graft or secondary closure in 16 cases (48.5%), rotational flap in 12 cases (31.4%) and free flap in 5 cases (15.1%). 4. The incidence of complications were as follows:limitation of motion in 22 cases (66.7%), pin tract infection in 16 cases (51.5%) (mild in 39.4%, severe in 12.1%), malunion in 15 cases (45.5%), delayed union in 14 cases (42.4%), bone infection in 8 cases (24.2%), refracture in 1 case (3.0%) and compartment syndrome in 1 case (3.0%). 5. Overall functional results which were evaluated according to a scoring system modified from Karlstrom and Orelud were good in 4 cases (12.1%), satisfactory in 11 cases (33.3%), fair in 12 cases (36.4%) and poor in 6 cases (18.2%). The functional result of 3b fractures was poorest.