In August 2006, the new AZ Alkmaar soccer stadium (capacity 17,000) opened. To provide adequate emergency support, medical teams of Red Cross volunteers and coronary care unit and emergency room nurses were formed, and facilities including automated external defibrillators were made available at the stadium. During every match, 3 teams are placed among the spectators. All patients who had cardiac events were stabilized by the teams and transported to the hospital. They formed the study group. From August 2006 to May 2007, >800,000 individuals attended soccer matches at the new stadium. Four cardiac events (3 out-of-hospital-resuscitations for ventricular fibrillation, 1 patient with chest pain) requiring emergency medical support occurred. On-site resuscitations using defibrillators were successful. Two patients with triple-vessel disease subsequently underwent coronary bypass surgery and implantable cardioverter-defibrillator implantation. One patient had single-vessel disease of the circumflex branch, for which he received a coronary stent. All had uneventful recoveries. An acute coronary syndrome was ruled out in the patient presenting with chest pain. In conclusion, the presence of emergency medical teams at a large sport stadium was of vital importance in the immediate care of critically ill patients. On-site resuscitation using automated external defibrillators was lifesaving in all cases. The presence of medical teams equipped with defibrillators and emergency action plans is recommended at large venues that host sports and other activities.