Headache is a common chief complaint in primary and ambulatory care settings. The etiology of headache is usually benign, its workup is often minimal and straightforward, and the clinical approach focuses primarily on symptom control. A small proportion of headaches is caused by subarachnoid hemorrhage (SAH), most of which are due to ruptured cerebral aneurysms. Such hemorrhage carries a high mortality, with significant rates of devastating disability among survivors. Misdiagnosis of SAH is frequent and results in medicolegal risk to the unwary physician. An organized, algorithmic approach emphasizes high risk historical and physical examination features that suggest SAH. Expeditious neuroimaging and lumbar puncture are employed to confirm suspected SAH. Diagnosis of SAH requires immediate stabilization, followed by neurosurgical consultation for definitive management. Transfer to high-volume neurosurgical and endovascular centers is associated with improved outcomes for SAH.