Massive irreparable rotator cuff tears (MIRCT) is a difficult clinical problem to treat in young, active individuals with minimal arthritis. Tendon transfers allow for donation of muscle units that can power the shoulder and restore kinematics. Posterosuperior rotator cuff deficiency can be treated with either a latissimus dorsi tendon or lower trapezius tendon transfer. The authors preferred method for treating irreparable supraspinatus and infraspinatus tears is with an arthroscopic assisted lower trapezius tendon transfer. The advantage of the lower trapezius tendon is that its vector is directly in line with the infraspinatus tendon allowing for better external rotation and abduction moment arms. The tendon is harvested from the spine of the scapula and augmented with an Achilles tendon allograft for length which is then secured at the footprint of the rotator cuff. Anterosuperior rotator cuff deficiency can be treated with a pectoralis major tendon or anterior latissimus tendon transfer. For subscapularis deficiency, our preferred method is an open versus arthroscopic latissimus tendon transfer. The tendon is harvested in the posterior axilla and augmented with an Achilles tendon allograft at the tendon interface to provide bulk. The tendon is passed arthroscopically to the anterior humerus and secured at the lesser tuberosity. Tendon transfers are a safe, reliable and reproducible technique when treating MIRCTs.