OBJECTIVE Reconstruction of active elbow flexion against gravity (strength grade > or =M(3)) by transfer of the latissimus dorsi muscle in order to improve the functionality of the upper extremity. METHODS Irreparable lesions of the musculocutaneous nerve (C(5)/6). Failure of regeneration after peripheral nerve reconstruction for the musculocutaneous nerve (neurolysis, suture, nerve grafting). Brachial plexus injury (lesions to the upper part, C(5)/6). Loss of biceps function due to trauma, ischemia, poliomyelitis or tumor. METHODS Possible recovery of biceps function by reinnervation, spontaneously or after nerve reconstruction. Weakness of the latissimus dorsi muscle (strength grade < M(4)). Insufficient passive range of motion of the elbow joint (osteoarthritis, contracture). Lack of motivation, reliability, and cooperation of the patient in postoperative rehabilitation program. METHODS The intact latissimus dorsi muscle is transferred with its origin and insertion ventrally and sutured with its thoracic aponeurosis into the insertion of the biceps tendon in order to act as an elbow flexor. METHODS Following postoperative immobilization in an upper-arm Gilchrist bandage at 100 degrees flexion and supination (or neutral position, but not pronation) of the forearm for 6 weeks, passive motion exercises of the elbow are started. Active flexion and extension exercises begin at 8-10 weeks postoperatively. To prevent the deleterious effect of muscle and tendon elongation, an orthosis is used during the night to keep the elbow flexed at 90 degrees for 6 months. RESULTS According to the authors' experience and the results reported in the literature, bipolar latissimus dorsi muscle transfer is a reliable method to restore functional elbow flexion regarding range of motion (> 90 degrees elbow flexion) and strength (at least antigravity strength, > or =M(3)) with acceptable donor morbidity and complication rate.