Aiming to evaluate the efficacy of anterior acromioplasty in the treatment of subacromial impingement syndrome, prospective studies in 33 shoulders of 31 patients were carried out. Of these patients, 25 were female, 6 were male, and their average age at time of operation was 55 years (between 20-76 years). 12 shoulders of 10 patients were classified as stage 2, and 21 shoulders of 21 patients a stage 3. Except for those with traumatic rotator cuff tears, all shoulders initially received conservative therapy for an average of 5.5 months, and operation was planned when inadequate improvement was detected. Anterior acromioplasty was performed on all shoulders, and in 19 shoulders at stage 3, rotator cuff repair was also carried out. Follow-up period was 15 months in average. Following surgery, stage 2 shoulders showed an increase of 39 points in average in the Constant score; pain had totally disappeared in 75% of patients and had decreased in 25% 70% of these patients reported excellent results as compared to their preoperative states, 20% reported better results and 10% no change at all. Stage 3 shoulders exhibited an increase of 42 points in average in the constant score; in 80% pain had totally disappeared and in 20% had partially ceased. 13 patients (87%) in this group reported excellent postoperative results, while 2 patients (13%) reported better results. These findings demonstrate that, for stage 2 and 3 subacromial impingement syndromes, anterior acromioplasty and when necessary, rotator cuff repair give successful results, concerning especially complaints like pain and functional disability.