Background Excellent clinical results of arthroscopic surgical repair have been reported for rotator cuff tears, however treatment of large and massive rotator cuff tears remains challenging. We have performed single row repairs with graft augmentation of fascia lata for large and massive rotator cuff tears in order to reduce a tension at the tendon-bone repair site for prevention from retear of the repaired rotator cuff. The purpose of this study was to evaluate clinical outcomes and rotator cuff integrity after arthroscopic rotator cuff repair (ARCR) with graft augmentation of the fascia lata. Material and methods Nineteen patients who underwent ARCR but unable to perform footprint fixation were included. These patients (14 males and 5 females), with an average age of 66.2 years old (range; 52–79 year old), were diagnosed with a large and massive rotator cuff tear. Single row repairs with footprint medialization were performed in 7 cases (SR group) and graft augmentation of fascia lata in addition to single row repairs were done in 12 cases (GA group). MRI was assessed at 6 and 12 months postoperatively and a retear was defined as discontinuity of the repaired supraspinatus tendon. Japanese Orthopaedic Association (JOA) score, UCLA score, and Constant score were assessed as clinical outcomes. Results MRI examinations revealed 6 retears out of 7 SR cases (re-tear rate: 85%) and 2 cases out of 12 GA cases (re-tear rate: 17%) at 6 months postoperatively. There was no additional retear at 12 months. JOA score, UCLA score, and Constant score in both groups significantly improved at the final follow-up, but there was no statistical difference between both groups on each score. The abduction strength significantly improved only in the GA group. Discussion In the present study, ARCR with graft augmentation of fascia lata for large and massive rotator cuff tears showed good clinical scores with a low retear rate and improvement of abduction strength. The low retear rate might be due to reduction of tension at the cuff repair site. Therefore, graft augmentation of fascia lata would be a useful option for large and massive rotator cuff tears.