Sudden cardiac death (SCD) claims approximately 460,000 lives per year in the United States, and half of these deaths occur in people with a history of coronary artery disease. Patients with left ventricular dysfunction and a history of myocardial infarction are at especially high risk. There is now strong evidence from multiple well-designed randomized controlled trials that implantable cardioverter defibrillators (ICDs) save lives when used for both primary and secondary prevention. As indications for ICD implantation have broadened, considerable debate has taken place because of the substantial cost involved in widespread ICD utilization. This article summarizes the epidemiology of SCD, reviews the evidence supporting the use of ICDs in patients with ischemic cardiomyopathy, and explores some of the controversy surrounding ICD utilization that has arisen in the wake of recent trials that have utilized ICDs for the primary prevention of SCD.