Twenty-six cases of non-neoplastic stenosis of the aqueduct are reviewed. This condition may take a very chronic course and may not be revealed until decompensation of hydrocephalus takes place. Poor athletic record in the school or intellectual impairment in early life, commonly overlooked, can presage the more obvious symptoms. A prolonged follow-up of these cases is essential to exclude a slowly growing neoplasm near the aqueduct. Our management and the outcome of these cases is discussed.