The CT finding of 98 patients with subarachnoid hemorrhage due to aneurysmal rupture were analysed andcompared with cerebral angiography for the purpose of preangiographic prediction of aneurysmal location as well asevaluation of the CT features corresponding to the vasospasm or ischemic neurologic dysfunctions. The results wereas follows. 1. Aneurysms could be identified on initial cerebral angiography in 82 out of 98 patients withsubarachnoid hemorrhage and anterior communicating artery aneurysms were most common (42 cases), followed by MCA,posterior communicating artery. ICA, basilar artery in order of frequency. 2. The CT findings of those patientswere hemorrhage in subarachnoid space(69%). localized hematoma(47%), ventricular dilatation(31%), enhancingnodule(23%), cisternal enhancement(20%), cerebral infarction(15%), ventricular hemorrhage(14%), and epiduralhemorrhage(3%). 3. Localized hematoma was more prevalent in anterior communicating artery aneurysm rutpure(54%),and less frequently in MCA, posterior communicating artery and ICA aneurysms. 4. Most of aneurysmal sac could beidentified as enhancing nodule on CT when the real size were over 1cm. 5.The site of ruptured aneurysm could bepredicted in many patients wiht ACA and MCA aneurysm according to the CT featurs such as hemorrhagic patterns,location of hematomas or enhancing nodules. 6. Localized hematoma or blood clots and cerbral infarction areconsidered to be the CT featurs corresponding to the angiographic vasospasm.