This prospective study determined whether single-row anchor fixation would reliably improve clinical outcome and maintain structural integrity after arthroscopic repair of single-tendon and 2-tendon rotator cuff tears. In 39 patients, 21 shoulders had single-tendon tears and 18 had 2-tendon tears. Mean follow-up was 38 months (minimum, 24 months). A standardized assessment was done preoperatively and postoperatively at yearly intervals. Postoperative magnetic resonance imaging (MRI) was performed at a minimum 1-year follow-up. Mean forward elevation, pain, satisfaction, and American Shoulder and Elbow Surgeons scores significantly improved for both groups (P < .01). Postoperative MRI examinations showed 19 cuffs (90%) were intact for single-tendon tears and 15 (83%) were intact for 2-tendon tears. A recurrent tear on postoperative MRI was significantly correlated with the intraoperative finding of asymmetric retraction. Arthroscopic rotator cuff repair using single-row anchor fixation resulted in significant improvements in clinical outcome and reliable repair integrity for both single-tendon and 2-tendon tears.