Seven cases of primary intraventricular hemorrhage (PIVH) constituted 3.1% of intracerebral hemorrhages in a prospective stroke series of 2,950 patients. All patients collapsed suddenly and had a depressed state of consciousness. Focal signs, if present, were minimal and contralateral to the major site of hematoma. Angiography in four patients revealed three intracranial arteriovenous malformations and one moyamoya. We conclude that PIVH may be readily diagnosed radiologically and underlying vessel malformations should be sought by angiography. Survival is common (five of seven cases), but a severe amnesic state may be a persisting deficit.