In the treament of the non-union or delayed union of the long bone, it is very difficult to achieve union. We have experienced 15 cases of non-union or delayed union of the tibia who were treated by sliding inlay bone graft with cancellous chip bone graft from June, 1979 to April, 1984. The results were as follows: l. In all cases cancellous iliac bone graft were performed, and additionally internal fixation or simple cast immobilization were done for stabilization of the fracture site. 2. The average bone union time was 2.8 months in delayed union and 4.4 months in non-union. 3. 1n 5 failed cases there were reactivation of previous infections. 4. In 5 cases of postoperative infection, sliding grafts were sequestrated in all. 5. The advantage of this procedure in the cases without infection were: 1) In the anteromedial cortex of tibia, such a surgical intervention permits easy skin closure and prevents skin necrosis. 2) Such a procedure can recanalize the obliterated medullary cavity without disturbance of the fracture ends during operation. 6. This procedure was proved to be one of valuable adjuvant method in the treatment of uninfected non or delayed union of the tibiae.