Injury to the musculocutaneous nerve leads to devastating functional loss of the arm. The ulnar nerve transfer to the musculocutaneous nerve was first described in 1994 by Oberlin and has become a popular and reliable method to restore elbow flexion. The flexor carpi ulnaris (FCU) branch is coapted to the biceps branch of the musculocutaneous nerve. The FCU assists in forearm supination, making this transfer synergistic and intuitive. Postoperative therapy includes three phases based on the donor activation focused rehabilitation approach (DAFRA). Therapy progresses based on results of monthly manual muscle testing of the recipient biceps muscle. Frequent donor activation with active or resisted wrist flexion is encouraged throughout the first two phases. Exercises and functional activities that combine donor motion with active (and active-assisted) elbow flexion in supination are included in the motor reeducation program. Functional strength of the biceps may not be observed until 12 months from surgery.