The relationship between traumatic brain injuries and associated peripheral nerve injuries has not been previously studied in children in the rehabilitation setting. One hundred and fifty-seven consecutive admissions of brain-injured children were included in this prospective study to determine the frequency and pattern of recovery of peripheral nerve injuries in such patients. Twelve patients met the clinical diagnostic criteria for peripheral nerve injury. Electrodiagnostic studies confirmed the clinical diagnosis in 11 (7%) patients. Grading of spontaneous activity and electrodiagnostic study of the contralateral limb were used to differentiate electromyographic abnormalities due to upper motor neuron lesion and nerve injury. Electrodiagnostic study was useful to confirm clinical diagnosis and predict prognosis of nerve injuries. Two patients developed preventable pressure neuropathy. Eight patients showed moderate or full recovery in 9-10 months post-injury. All children with severe brain injuries should be evaluated for concomitant peripheral nerve injuries.