The incidences of posttraumatic avascular necrosis of the femoral head were variably reported. In 1980, Calandruccio reported its incidence of 14% in nondisplaced femoral neck fracture and 50% in displaced ones. In general, the prophylactic methods, such as core decompression, bone graft and trochanteric osteotomy were recommended for the treatment of early stages of femoral head avascular necrosis(Ficat-Arlet stage 1 or 2), while the primary replacement surgery for the advanced ones (Ficat-Arlet stage 3 or 4). One of our authors(Y.K. Chung) has performed five cases of corticocancellous bone grafts using combined autogenous free fibular graft and iliac cancellous bone graft, for the post-traumatic femoral head AVN from January 1985 to December 1989 at our hospital, and the following results are obtained: 1. Among the forty nine displaced adult femoral neck fractures, there were five eases of avascular necrosis(10. 2%). 2. There were three male patients and two female ones, and the average age of injury was 48 years old(30 to 57). 3. According to the type of fractures, there were four cases of subcapital fracture and one of transcervical fracture. All of the patients were performed closed reduction and internal fixation with compression hip screw system, including additional Knowles pinning in two cases. 4. Histological study with the excised femoral head, showed that there was no bony union between the grafted cancellous bone and the necrotic head, and the grafted bone has been changed to amorphous necrotic tissue. However, we found a solid consolidation of the grafted bone and the femoral neck portion.