Rupture of anterior communicating artery aneurysm is one of the most important casuses of subarachnoid hemorrhage. Subarachnoid hemorrhage due to ruptured anterior communicating artery aneurysm shows characteristic CT findings. such as forntal hematoma or septum pellucidum hematoma. In some patients with the ruptured aneurysm direct carotid angiography may be needed. particularly when transfemoral approach is not possible. However, not much have been known about the puncture site selection between the two carotid arteries in relation to the location of hematoma in CT scans. To determine the ideal puncture site of the direct carotid angiography, seventy-five cases of anterior communicating artery aneurysm confirmed by operation from May 1988 to April 1992, were analyzed in terms of relationship between location of hematoma on CT, direction of aneurysm and Al artery on angiograms. Frontal lobar hematoma was more prevalent than septal hematoma, and was more common on the right side. In cases of lobar hematoma, aneurysm was directed to the ipsilateral side of the hematoma(67%) and was most commonly fed by contralateral Al artery (75%) Septal hematoma consisted 36% of the cases and among them, midline directed aneurysm was most common, frequently fed by left Al artery. In conclusion, when performing direct carotid angiography in patients with anterior communicating artery aneurysm. if forntal hematoma is observed on CT, it may be beneficial to puncture contralateral carotid artery. Meanwhile, if hemorrhage of septum pellucidum is observed, it may be better to puncture left carotid artery.