Hakim and Adams and co-workers had pointed out that hydrocephalus with normal CSF pressure may produce signs of mental deterioration, progressive gait difficulties and signs of involvement of the pyramidal and extrapyramidal systems; the mental changes at the final stages of the disease may resemble the so called akinetic mutism and patients improved with ventriculo-atrial shunt operations. A case of a 61 year old male in which these signs and symptoms developed over a period of two years is reported. The patient was first admitted to a hospital on April, 1968 reporting progressive difficulty to walk. The neurological examination at this time demonstrated only brisk generalized tendon jerks and a paretic gait; routine investigations (CSF, blood and urine) were inconclusive. The patient was discharged with a suspected diagnosis of myelopathy due to a mild cervical spondylosis demonstrated by radiologic examination. On November-1968 he was brought to the hospital due to the rapid deterioration of his gait and signs of impairment of mental functions. On examination he presented severe impairment of the mental functions, incontinence of urine and feces and bilateral pyramidal signs. There were no serious illnesses in his previous history. Air and pantopaque-ventriculogram demonstrated a communicating hydrocephalus. A ventriculo-atrial shunt operation was performed, followed by complete recovery.