The intercostal nerve (ICN) to musculocutaneous nerve (MCN) transfer is a surgical procedure to regain elbow flexion in patients with a severe brachial plexus traction injury. This extraplexal to intraplexal nerve transfer has been applied for patients with root avulsion injury since the 1960s but has lost popularity due to the rise of intraplexal nerve transfers, especially the ulnar nerve fascicular transfer. It remains the preferred options for adult patients with C5-T1 root avulsions and has proven to be reliable provided that the post trauma delay is relatively short. In birth injuries, the ICN-MCN nerve transfer is a valuable treatment option if the viable roots are needed to reinnervate the hand.