Isolated musculocutaneous nerve injury is extremely rare. The few reported cases were associated with heavy exercises and violent extension of the forearm. The lesions in those cases were below the coracobrachialis muscle, involving the biceps, brachialis, and cutaneous nerves of the forearm. This patient's lesion was unique, located proximal to the coracobrachialis. There was no antecedent trauma. At follow-up six weeks and four months after onset of symptoms, significant improvement was noted both clinically and electrophysiologically. Musculocutaneous nerve palsy is important to distinguish in certain differential diagnoses, particularly with C5 or C6 radiculopathy and brachial plexus injury.