From 1980 to 1984, 72 patients with impingement syndrome were treated by anterior acromioplasty before they developed rotator cuff tears. Follow-up evaluations averaged 23 months (range, five to 48 months). The average age was 42 years (range, 23-61 years). Preoperatively, 80% of the patients had pain at rest; the other 20% complained of pain during moderate activity. At the time of follow-up examination, 89% showed significant improvement, while 11% remained unchanged. Thirty-seven percent of the patients had varying degrees of muscle weakness preoperatively; of these, 71% were improved, 21% were unchanged, and 8% had a further decrease in the range of motion postoperatively. The results indicate that anterior acromioplasty is an excellent procedure for relief of pain due to impingement. Additionally, beneficial results were obtained in range of motion and muscle strength. In only a few select cases was lateral clavicle excision or tenodesis of the long head of the biceps necessary. Caution is advised in allowing return to strenuous activity unless the patient has recovered adequate strength in the cuff musculature.