The surgical indication and techniques of intracranial arteriovenous malformations are discussed, on the basis of 203 experiences with AVMs. A special key point in our surgical techniques is described as follows. The feeding arteries of the AVM--or the main artery at the base of the brain, which is the original source of the feeding artery--are identified and prepared, and then temporary clips are placed on these arteries to produce vascular occlusion prior to the dissection of the AVM itself. During these procedures, 20% of mannitol should be administered to prolong the permissible time of cerebral artery occlusion. The administration method of mannitol is described in detail including dose and time schedule. The new prolongation method of temporary occlusion time, for which mannitol with fluorochemicals permits longer occlusion time, is also introduced.