Recently, advances in arthroscopic techniques have allowed shoulder surgeons to perform fully arthroscopic repair of full-thickness tears. Outcome data have shown that improvement is inconsistent between studies. We performed a retrospective review of 105 consecutive patients who underwent arthroscopic rotator cuff repair from 1999 to 2002. Preoperative and postoperative evaluation consisted of a history, questionnaire, and examination to determine American Shoulder and Elbow Surgeons, Constant, and visual analog pain scores. Complete data were available for a minimum of 12 months (range, 12-45 months) for 71 patients. Increases in range of motion and outcome scores and associated reductions in visual analog scores were all significant. With massive tears, scores and pain were significantly improved. Arthroscopic rotator cuff repair reliably improves functional deficits and pain regardless of tear size. Smaller tears yield significant improvement in American Shoulder and Elbow Surgeons, Constant, and pain scores. Functional improvement was seen with massive tears, but gains in strength and motion were less dramatic.