In contrast to the current consensus that governs the mechanics of prehospital advanced cardiac life support (ACLS), uniform criteria for determining when to initiate, withhold, or terminate ACLS in the field do not exist. Most emergency medical services (EMS) permit paramedics and other prehospital providers to withhold resuscitation when the victim obviously is dead, but the accuracy and appropriateness of this judgement in the field have not been subjected to empiric research. Do-not-resuscitate orders on patients in community settings often are problematic when paramedics and other prehospital providers are governed by standing orders that require them to initiate CPR when it is indicated medically. To date, eight states and a number of local EMS systems have developed a variety of policies to address this dilemma. Currently, few services permit paramedics to terminate ACLS in the field when such efforts fail to achieve return of spontaneous circulation. Studies have demonstrated convincingly that the rapid transport of such patients for further attempts at resuscitation in the hospital yields dismal rates of survival. The costs, risks, and benefits of this practice in community settings must be reviewed carefully to allocate EMS resources in an optimal manner.