The authors report a 49-year-old man who presented with obstructive hydrocephalus caused by a thrombosed posterior cerebral artery aneurysm. He underwent an endoscopic third ventriculostomy for the obstructive hydrocephalus followed by endovascular occlusion for the aneurysm. To our knowledge, this is the first report of a thrombosed posterior cerebral artery aneurysm presenting with obstructive hydrocephalus treated by the combination of endoscopic and endovascular techniques.