This study reanalyzes a group of patients who had anterior acromioplasty between 1975 and 1979, whose results were reported in 1990 at a mean 8-year follow-up, to identify any continuing problems or new complications, to assess the frequency of further surgery, and to define long-term outcome. Thirty-two patients were included. The mean follow-up was 25 years (range, 21 to 27 years). All had the impingement syndrome. At surgery, there was tendon and bursal inflammation with fibrosis in 28 shoulders and a small rotator cuff tear in 4. Five shoulders have required additional surgery: distal clavicle excision in one, revision anterior acromioplasty in one, and repair of a new rotator cuff tear in three. Of the shoulders, 23 (72%) were reported as having no or slight pain. Positive patient satisfaction was expressed in 28 (88%). Comparisons were made to the opposite shoulder in this older patient group. The mean within-patient difference between the operative shoulder and the opposite shoulder on the Simple Shoulder Test was 0.4, with scores of 8.9 for the operative side and 9.3 for the opposite side (P = .47). The mean difference in the American Shoulder and Elbow Surgeon's score was 8.6 points, with scores of 75 for the operative side and 83 for the opposite side (P = .02). The results of open acromioplasty for the impingement syndrome are usually maintained over time. Acromioplasty does not always prevent the need for subsequent rotator cuff surgery, but the rate of reoperation has remained relatively low in the long follow-up period.