Rapid delivery of defibrillatory shocks increases survival in patients with cardiac arrest. The automated external defibrillator interprets cardiac rhythms and delivers electrical shocks, permitting appropriate defibrillation by persons with minimal training. California initiated a program for early defibrillation by basic emergency medical technicians, using manual or automated external defibrillators, and by public safety personnel (fire fighters, peace officers, and public lifeguards), using automated external defibrillators. The program includes a system for reporting outcomes statewide. In the first 46 months under this program, 1487 patients received defibrillatory shocks; 1009 (68%) of these patients had witnessed ventricular fibrillation. Of the latter group, 191 were discharged from the hospital, representing 19% of those with witnessed ventricular fibrillation and 13% of all patients who had had shocks applied. California also implemented a framework of training and medical direction for defibrillation by laypersons using automated external defibrillators. Early defibrillation by basic emergency medical technicians and public safety personnel, encouraged by appropriate regulatory changes, results in gratifying survival rates.