A 28-year-old man with von Recklinghausen's neurofibromatosis was first seen with a spastic-ataxic gait and epileptic seizures of recent onset. computerized tomographic scan established the diagnosis of aqueductal stenosis, rarely reported in patients with von Recklinghausen's disease. The value of computerized tomography in the etiological diagnosis of hydrocephalus in von Recklinghausen's disease is emphasized and the pathogenesis of aqueductal narrowing in neurofibromatosis is discussed.