Subarachnoid hemorrhage (SAH) is an important cause of death and serious morbidity, accounting for about 10% of all cases of stroke. In spite of recent advances in the surgical treatment of aneurysms and arteriovenous malformations (AVMs), the overall morbidity associated with SAH has changed little over the last several decades. A greater awareness by the medical community of the warning signs of SAH is essential in effectively reducing the morbidity associated with this illness. With modern surgical techniques, most aneurysms and many AVMs can be obliterated safely and effectively if detected early, before they result in a major SAH.