To determine the prognosis and the best treatment for patients who have femoral head fractures associated with traumatic posterior hip dislocations, we reviewed the clinical records of from 1985 to 1991 and selected the cases of 12 patients(12 femoral head fractures associated with posterior hip dislocation) for further reviews. The longest follow-up was 5 years and 1 month and the shortest 6 months, the average being 2 years and 6 months. The results were as follows: 1. The incidence of femoral head fracture was 12 cases(31%) of 39 posterior hip dislocations. 2. The most common cause was traffic accidents and Pipkin type 1V fractures dislocation was most common, 6 of 12 cases. 3. The prognosis was good when the early reduction had been carried out in Pipkin type I II or 1V injury. But, the severity of the acetabular fracture was the factor that determine the pragnosis in Pipkin type 1V injury. 4. The good prognosis is expected when early open reduction has been carried out in inadequate close reduction of hip or femoral head fracture and in the cases of loose fragments within the hip joint.