We have assessed the efficacy of free nerve grafts in 90 cases of brachial plexus injury. Relatively good recovery of the elbow flexor and extensor muscles and of those of the shoulder girdle was found but recovery of the flexors and extensors of the forearm and of the intrinsic muscles of the hand was extremely poor. Poor results were found when spinal nerve roots seemed normal to the touch and appeared intact but had abnormal somatosensory evoked potentials or myelography. Recovery of the deltoid and infraspinatus muscles was better when injury had occurred to the circumflex and suprascapular nerves rather than to the plexus itself, perhaps because these nerves were explored in their entirety to determine the presence of multiple lesions. It is important to visualise the entire nerve thoroughly to assess the overall condition. Thorough exploration of the plexus and the use of intraoperative recording of somatosensory evoked potentials are essential