Twenty-four nonunions (femur-9, tibia-13, humerus-2) were treated with the Ilizarov external fixator. The main causes of nonunions were infection, insecure fixation in reduced fractures, and severe soft injury. Of 24 nonunions, 15 had the preoperative bone shortening ranged from 1cm to 5cm, and 10 had bone defect ranged from 2cm to 17cm after removal of infected bone and soft tissue. The treatments of 24 nonunions were monofocal osteosynthesis in 12, bifocal osteosynthesis in 10, and trifocal osteosynthesis in 2 nonunions. The transverse transport wires and half pins were used in bifocal and trifocal osteosynthesis. The cancellous bone grafts were done in 22 of 24 nonunions. The mean union time was 3.5 months in monofocal osteosynthesis; 6 months in monofocal osteosynthesis with bone graft; 10 months in bifocal osteosynthesis; 9 months in bifocal osteosynthesis with bone graft; 10 months in trifocal osteosynthesis with bone graft. Of 15 complications developed, 6 were adjacent joint stiffnesses, 3 were residual bone shorteninges (>2cm), 3 were axial deviations, 2 were delayed consolidations, and 1 was refracture. Nine of 15 complications were treated with conservative method and surgical method, and six were untreated.