Massive irreparable rotator cuff tears are often associated with severe functional impairment and disabling pain. One viable treatment option is a latissimus dorsi tendon transfer. We propose an all-arthroscopic technique that we believe avoids insult to the deltoid musculature while reducing morbidity from open harvest of the tendon. The operation is performed with the patient in the lateral decubitus position, by use of a combination of viewing and working portals in the axilla. The initial viewing portal is placed along the anterior belly of the latissimus muscle in the axilla. The latissimus and teres major are identified, as is the thoracodorsal neurovascular pedicle. The tendons are carefully separated, and the inferior and superior borders of the latissimus are whipstitched using a suture passer, which helps facilitate subsequent mobilization of the muscle. The interval deep to the deltoid and superficial to the teres minor is developed into a subdeltoid tunnel for arthroscopic tendon transfer. The latissimus tendon is then transferred and stabilized arthroscopically to the supraspinatus footprint with suture anchors. Our preliminary data suggest that this surgical technique results in improvement in pain, range of motion, and function.