A prospective study was performed to determine the accuracy of arthrography compared with ultrasonography in the evaluation of thirty-two patients who had a degenerative lesion of the rotator cuff. Both tests were done preoperatively, and the condition of the rotator cuff was determined intraoperatively. Arthrography was accurate in the diagnosis of twenty-eight (87 per cent) of the thirty-two patients (twenty who had a full-thickness tear, seven who had a partial-thickness tear, and five who had an untorn rotator cuff and tendinitis), while ultrasonography was diagnostic in only twelve (37 per cent). In this specific population of patients, arthrography was found to be superior to ultrasonography.