AbstractThe incidence of subarachnoid hemorrhage is estimated at 5 to 10 per 100,000 per year. In patients who survive the initial hemorrhage, the repeat hemorrhage rate is 15% to 20% in the first 2 weeks after presentation and is associated with devastating clinical outcomes even graver than the initial rupture. The current options for aneurysm treatment are surgical clipping and, since the mid‐1990s, neuroendovascular coil embolization. The former was at one time the gold standard of care, but consistent with the trend in modern medicine toward less‐invasive procedures, the latter has steadily gained prominence. Although there is still controversy as to its long‐term durability and safety, it is now the preferred procedure. This article describes the procedure's antecedents, rationale, and essential components. Mt Sinai J Med 77:279–285, 2010. © 2010 Mount Sinai School of Medicine