One hundred fifty-six Charnley low-friction arthroplasties performed in patients 50 years of age or younger are reviewed. Excluding sepsis, survivorship analysis showed a 12% probability of mechanical failure at 10 years. The detailed clinical and radiological results of 130 hips with a 3-16-year follow-up period are presented. Revision surgery was required in 14 hips (10.8%), for the following reasons: sepsis (2.3%), loose sockets (2.3%), loose stems (5.4%), and stem fracture (0.8%). Evidence of radiological loosening indicative of pending failure was present in 14 hips (12.0%). At 10 years the predicted failure rate of the surviving hips was 12%.