Aqueductal stenosis is induced by widely various causes. These causes include congenital stenosis, tumor or inflammation. Among them vascular malformation is a very rare cause. In this paper we present a rare case of aqueductal stenosis caused by venous angioma. The patient was a 28-year-old female, who suffered from headache and double vision. On admission, CT and MRI showed lateral and third ventricular dilatation not but fourth ventricle, suggested aqueductal stenosis. Gd-DTPA enhanced T1-weighted MR image showed an abnormal draining vein passing through the orifice of the aqueduct. Angiography demonstrated the umbrella sign which was specific sign of the venous angioma. We performed endoscopic third ventriculostomy. Postoperative neuroradiological examination showed shrinkage of the ventricles and the symptom of the patient improved markedly. In the past literatures, five cases of aqueductal stenosis due to venous angioma have been reported. Although venous angioma is congenital, all five cases had been symptomatic at adult stage. Detailed evaluation of pre-and post-operative MRIs suggest that aqueductal stenosis induced enlargement of the lateral and third ventricles, which led narrowing of the suprachiasmatic cistern and the peri-mesencephalic cistern, and downward displacement of medulla and tonsil into the foramen magnum. As a result, hydrocephalus is aggravated gradually.