This study concerns the fate of the first 100 Charnley total hip replacements done in ninety ninety patients at The Hospital for Special Surgery. At the time of this study, the follow-up of the surviving sixty-seven patients ranged from nine and one-half to eleven and one-half year (average, ten years). When studied at an average of ten years after the initial operation, twenty-six of the original 100 hips that had been operated on had been lost to follow-up due to death, and seven could not be traced. Of the remaining sixty-seven hips that were available for clinical evaluation, thirty-seven were rated as excellent; twenty-two, as good; four, as fair; and four, as poor, according to The Hospital for Special Surgery scoring system. The radiographs of fifty-four of the sixty-seven hips were available for this evaluation. Twenty-three of these hips showed radiographic signs of problems that appeared to have no significant bearing on the quality of their clinical results. There was loosening of the femoral component in five hips which occurred within the first three years after operation and then apparently stabilized. One required reoperation eight years after the original surgery. There was one fracture of the femoral stem eight years after the original operation, requiring reoperation. Six hips demonstrated so-called calcar resorption, the greatest measuring fourteen and thirty millimeters. Ten acetabular components showed wear of more than one millimeter, the maximum being five millimeters in both components of a patient with bilateral hip replacement. Two acetabular components migrated, one requiring reoperation due to progressive bone loss nine and one-half years after the original procedure. All three reoperations have been successful to date.