Patients, families, and physicians frequently decide that a hospitalized patient will forgo cardiopulmonary resuscitation and document this decision with a do-not-resuscitate (DNR) order. In community settings (home, nursing home, hospice), these orders may conflict with paramedics' standing orders to provide cardiopulmonary resuscitation whenever it is medically indicated. We did a nationwide telephone survey of state offices for coordination of emergency medical services (EMS) to see how the states deal with this potential conflict. We identified eight states that have specific policies enabling EMS personnel to accept DNR orders for patients being transported by ambulance. State officials identified administrative complexities and legal concerns as the primary barriers to enacting prehospitalization DNR policies. We also identified 21 local EMS systems that have developed policies for accepting orders to withhold life-sustaining treatment. Four types of policy models, characterized according to procedure for validating DNR orders and telephone accessing the EMS system, show that regulatory reform can address policy barriers in the absence of enabling legislation.