The ICLH (Imperial College-London Hospital) double cup hip replacement as it exists today consists of a metal femoral component which caps the femur and a polyethylene acetabular component which resurfaces the acetabulum. Both components are cemented in place. The first prosthesis was inserted in 1972 and during the following two years complications emerged which necessitated changes in the prosthesis and the operative technique. Since November 1974 there have been no changes in the prosthetic design or operative procedure and complications have been infrequent. An approach has been developed whereby trochanteric osteotomy is not necessary. Up to December 1977 159 hips were replaced in 154 patients. Clinically, the results of a successful double cup arthroplasty are similar to those obtained by conventional hip replacement. No deterioration in the quality of the results is suggested when early results are compared with those of patients who are now two years and longer since surgery. Technical errors to be avoided are varus placement of the femoral component and excessive vertical placement of the acetabular component. Conclusions drawn are tentative due to the fact that to date the follow-up period is inadequate.