As a means of providing defibrillation as soon as possible for those suffering out-of-hospital ventricular fibrillation, numerous communities have trained and authorized emergency medical technicians (EMTs) to provide defibrillatory shocks (EMT-D). The findings of four controlled studies and the experience of various communities have answered important questions. EMT-D programs have been shown effective in urban, suburban, and rural communities with and without paramedic backup. EMT-D programs appear safe, with errors of commission being extremely rare and errors of omission being of acceptably low incidence. Issues still to be resolved include the degree and amount of training that should be given and whether manual or automatic defibrillators should be used. Medical supervision and quality control is the most important aspect of EMT-D programs. At its core, the success of EMT-D programs is confirmation of the principle of early defibrillation. Wider dissemination of early defibrillation will improve survival from sudden cardiac death.