In a prospective study of 327 total hip arthroplasties using the McKee-Farrar prosthesis the patients were followed up each year for up to 8 years after the operation. The immediate results concerning pain and to some extent walking capacity and mobility were good in up to 90 per cent of cases. The excellence of the results declines with time, and after 7 years "good" results were noted in about 50 per cent. The infection rate without prophylactic antibiotics was 3.4 per cent and the rate of aseptic loosening 16 per cent. In elderly patients total arthroplasty is the operation of choice, but in younger patients one should be more restrictive.