A child with neurofibromatosis had hypertension and acute hemiplegia resulting from both renal and cerebral vascular occlusive disease. This case illustrates the importance of recognizing both these complications of neurofibromatosis. Vigorous medical and surgical antihypertensive therapy was attempted, and may have contributed to rapid neurologic deterioration. Children with neurofibromatosis and hypertension require a careful neurologic evaluation, including computed tomography, before therapy.