We reviewed the cases of thirty-six patients who had forty cemented total hip replacements with the Harris metal-backed acetabular component. The operations were done between 1972 and 1977, and the duration of follow-up averaged 7.6 years (range, five to 10.8 years). The average age of the patients was forty-four years (range, sixteen to sixty-two years). Aseptic loosening of the acetabular component occurred in three hips (7.5 per cent), and three more sockets were revised for other reasons. Two of the three sockets with aseptic loosening were in the fifteen patients (seventeen hips) who were forty-five years old or younger. The remaining loose cup was in one of the twenty-one patients (twenty-three hips) who were forty-six years old or older. The reduction in the rate of aseptic loosening of the socket in our series, compared with the higher rates reported in similar long-term studies in which other acetabular components were used, supports the conclusion that there is enhanced longevity of acetabular fixation when a metal-backed acetabular component is used in cemented total hip arthroplasty.