Thirty nine cases (38 patient) of acetabular fracture and fracture-dislocation were treated in our hospital during the period 1973 to 1977. The short summary of the observation were as follows; 1. Among 39 cases (24 were male and 15 female), the most common cause of acetabular fracture and fracture-dislocation was traffic accident. 2. The acetabular fractures and fracture-dislocations were treated by conservative measures in 25 cases and by open reduction in 14 cases. The results were as follows; excellent in 12(30%), good in 19(48%), fair in 5 (15%) and poor in 3 cases (7%). 3. Among 3 cases of poor results, secondary traumatic arthritis and limitation of motion were observed in two cases and aseptic necrosis of the femoral head, in one case. 4. The result of conservative treatment was satisfactory if the stability of the hip joint and the congruity of the superior weight bearing dome of the acetabulum was well preserved.