Intracranial aneurysms and their treatment is one of the leading problems of neurosurgery that create high mortality and morbidity. The technique of safe clipping is as generally used depends on the temporary occlusion of the cerebral vasculature during surgery. However, there is no exact data about temporary clipping or timing of this procedure. Preconditioning by exposure to sublethal hypoxic stress, hours or days before severe hypoxia, decreases cell death, and this resistance of the brain to injury is known as ischemic tolerance. Brief alternating periods of reperfusion-reocclusion at the beginning of reperfusion is defined as postconditioning. Cerebral ischemic pre/postconditioning protects against stroke, but is clinically feasible only when the occurrence of stroke is predictable. Brief, repetitive occlusion and release of the main trunk of a vessel during early aneurysm surgery or before long-lasting temporary artery occlusion may protect the brain against later possible vasospasm/ischemia.