A brachial plexus injury is the most severe nerve injury of the extremities. To achieve good results from treatment, correct diagnosis and early nerve repair are mandatory. The brachial plexus should be explored as early as possible if there is an incised wound, if clinical findings or diagnostic imaging indicate that at least one root is avulsed, if there is damage to the subclavian artery, and if there is total-type injury. With an upper-type injury with no clinical signs of a preganglionic lesion, the patient should be treated conservatively for 3 months and if there are no signs of recovery, then the brachial plexus should be explored. During this exploration, recording of the spinal cord evoked potential (ESCP) or the somatosensory evoked potential (SEP) is mandatory to determine the site of injury. Nerve grafting is indicated for a rupture in the root demonstrating a positive ESCP or SEP potential, in the trunk or in the cord. Exploration of the brachial plexus should be extended distally as far as possible to achieve good results after nerve grafting; when this was done more than M3 (MRC grading) power of the infraspinatus, deltoid, and biceps was achieved in more than 70% of our 32, 30, 33 patients, respectively. Results of nerve grafting for the forearm muscles have been very poor. Intercostal nerve transfer is recommended to restore elbow flexion in root avulsion type of injury, with elbow flexion to more than M3 being regained in 70% of our 221 patients. The best results of intercostal nerve transfer were achieved in patients younger than 30 years who received the operation within 6 months after injury. Motor recovery of hand function after intercostal nerve transfer was poor but protective sensation was restored in fingers innervated by the median nerve. The recommended treatment for each type of injury is described according to the results achieved.