This report presents the results of the senior author's initial twenty-five-year experience with the use of Charnley total hip arthroplasty with cement. The purpose of this paper was to evaluate the long-term results of total hip arthroplasty. Between July 1970 and April 1972, the senior author (R. C. J.) performed 330 Charnley total hip replacements with cement using a hand-packing cement technique in 262 patients. Fifty-one patients (sixty-two hips) who were alive at least twenty-five years post-operatively were evaluated from a clinical standpoint with use of a standard-terminology questionnaire. The average age of this group at the time of surgery was fifty-six years (range, thirty-five to seventy-one years) compared with sixty-five years (range, twenty-one to eighty-nine years) for the entire group. All patients were evaluated for radiographic changes at the time of their most recent follow-up. Of the fifty-one patients (sixty-two hips) who were alive at least twenty-five years postoperatively, thirty-one (thirty-six hips) had a follow-up radiograph made at a minimum of twenty-five years after the surgery. The average duration of radiographic follow-up for the fifty-one patients was 22.7 years (range, two to twenty-seven years). Of the sixty-two hips in the fifty-one patients who were alive at least twenty-five years postoperatively, fourteen (23 percent) had been revised. Three (5 percent) had the revision because of loosening with infection; eleven (18 percent), because of aseptic loosening; and none, because of dislocation. The prevalence of revision due to aseptic loosening of the acetabular component in all 316 hips (excluding those that were lost to follow-up or that were revised for infection or dislocation) was 6 percent (eighteen hips), whereas the prevalence in the fifty-nine hips (excluding the three revised for infection) in the patients who were alive at least twenty-five years after the arthroplasty was 15 percent (nine hips). The prevalence of revision because of aseptic loosening of the femoral component in all 316 hips was 3 percent (nine hips), and the prevalence in the fifty-nine hips in the living patients was 7 percent (four hips). In the group of living patients, osteolysis occurred in Gruen zone 1 or 7 in thirty-three hips and in Gruen zones 2 through 6 in two hips. Ballooning acetabular osteolysis occurred in five hips. Of the 327 hips for which the outcome was known after a minimum of twenty-five years, 295 (90 percent) had retained the original implants until the patient died or until the most recent follow-up examination. Of the sixty-two hips in patients who lived for at least twenty-five years after the surgery, forty-eight (77 percent) had retained the original prosthesis. Our follow-up study at twenty-five years following Charnley total hip arthroplasty with cement demonstrates the durability of the results of the procedure. These results should provide a means for comparison with the results of newer cementing techniques as well as those associated with newer cemented and cementless hip designs.