Seventy-one patients who had shoulder impingement syndrome were managed operatively with a modified Neer acromioplasty: thirty-seven, who had an intact rotator cuff, had a modified acromioplasty, and thirty-four, who had a torn cuff, had a modified acromioplasty and repair of the cuff. In the classic anterior acromioplasty as described by Neer, emphasis is placed on resection of the inferior prominence of the acromion. We believe that the removal of only the inferior prominence is insufficient, as often too much of the anterior aspect of the acromion protrudes beyond the anterior border of the clavicle. This portion of the acromion continues to irritate the subacromial bursa and the rotator cuff and to produce symptoms of impingement. Our modified acromioplasty is done in two steps: the portion of the acromion that projects anteriorly beyond the anterior border of the clavicle is resected vertically and then an anteroinferior acromioplasty is performed. We studied the results in patients who had been operated on by the senior one of us and who had been followed clinically for a minimum of two years. At the most recent follow-up visit, no difference in terms of pain and function was found between the patients who had had the modified acromioplasty only (Group I) and the patients who had had the modified acromioplasty and repair of the rotator cuff (Group II); thirty-three (89 per cent) of the patients in Group I and thirty (88 per cent) of those in Group II had a good or excellent result.