From 1978 to 1988, 14 giant intracranial aneurysms (more than 2.4 cm in diameter) and one large aneurysm (1.5 cm in diameter) were treated by extracranial/intracranial (EC/IC) bypass or cerebral artery reconstruction. Of the aneurysms, 10 were located at the intracavernous carotid artery (CCA). One of the 10 aneurysms was posttraumatic and located at both the carotid-ophthalmic artery segment and the bifurcation of the internal carotid artery (ICA). Three were seen at the middle cerebral artery (MCA) trunk. The aneurysms were demonstrated by angiography and CT scanning. They were treated with trapping of the aneurysm and superficial temporal artery (STA)/middle cerebral artery (STA-MCA) bypass with/without a graft (6 cases), cervical ICA ligation and STA-MCA bypass with/without a graft (6) aneurysm excision with an end-to-end anastomosis of the MCA and a STA-MCA bypass with a graft (1), proximal MCA occlusion and STA-MCA bypass with a graft (1), and aneurysm neck clipping following a STA-MCA bypass with a graft (1). The patients showed marked improvement after operation except one whose neurological deficit was aggravated temporarily. Postoperative angiography revealed that the anastomoses were patent in all cases. No surgical mortality or any delayed ischemic complications were noted after follow-up for 5.6 years. We believe that cerebral artery reconstruction or EC/IC bypass is still effective in the treatment of large and giant intracranial aneurysms.