The long-term outcome of treatment of posterior hip dislocations was studied in 60 patients. Thirty-two patients had concomitant fractures of the acetabular rim and seven had also femoral head fractures. Treatment consisted of immediate reduction, followed by gentle traction during one week and progressive weight-bearing over six weeks. Thirteen patients needed internal fixation of the acetabular fracture. Fourty-six patients could be followed for a median of 6.5 years. Fifteen patients, all with associated fractures, had late complications: peri-articular ossifications (5), avascular necrosis of the femoral head (1), mild osteo-arthrosis (5) and pain of unknown origin (4). No complications were noted in patients with simple posterior dislocation of the hip. Simple traumatic posterior hip dislocation has an excellent prognosis. Poor results only occur in case of associated fractures.