We analyzed the outcome after prehospital cardiac arrest in a part of greater Copenhagen. Four different emergency medical systems were acting: a system providing basic life support only (group 1), a system providing basic life support and early defibrillation (group 2), a system providing basic life support followed by advanced cardiac life support (group 3), and a system providing basic life support and early defibrillation followed by advanced cardiac life support (group 4). Over a 2-year period 624 cases of cardiac arrest were reported, 34 were discharged from hospital. The survival to discharge from hospital and the one-year survival were significantly better in group 4. Our data reconfirm that early advanced cardiac life support improves survival rates for prehospital cardiac arrest.