Cardiac arrest is an important public health problem and often occurs in the out-of-hospital setting in patients without a prior history of heart disease. Very few communities or emergency medical service (EMS) systems report survival rates for out-of-hospital cardiac arrest. Among those who do, survival rates vary substantially between cities, due in large part to community differences in the chain of survival. To improve survival in cardiac arrest, care must be optimized at each point along the cardiac arrest continuum, including a rapid emergency response, provision of cardiopulmonary resuscitation (CPR) by bystanders, delivery of high-quality chest compressions with minimal interruptions by first responders, rapid defibrillation, and optimization of postresuscitation care, including therapeutic hypothermia. Important current initiatives to improve cardiac arrest survival include hands-only CPR delivered by laypersons prior to the arrival of EMS, dispatcher-assisted CPR, and implementation of hospital-based therapeutic hypothermia protocols to improve postresuscitation care. Optimizing cardiac arrest survival requires a team effort between EMS directors, emergency physicians, cardiologists, hospital leadership, and the public. © 2010 Wiley Periodicals, Inc.