The clinical outcome of the cemented Charnley hip arthroplasty at follow-up periods of 16-25 years was evaluated retrospectively in patients aged 50 years or younger. One hundred thirty-two of a total of 167 hip arthroplasties were studied. The overall probability of survival of the implant at 20 years was 75% Survival of those with rheumatoid disease was 80% compared with 64% for those with osteoarthritis. Female sex was associated with a better prognosis. Accelerated wear was associated with decreased survival of the prosthesis. Varus orientation of the femoral component significantly influenced failure (P < .01). Radiographic loosening of the acetabular component was well tolerated, but loosening of the femoral component was significantly associated with pain (P = .01).