Defibrillation training within the Hong Kong Ambulance Service commenced in January 1991. Training supervision was provided by the Ambulance Service and the Hong Kong Medical Association. Practical examinations were given in which candidates had to perform the protocol satisfactorily. Defibrillator-equipped ambulances/motorcycles were despatched when a patient was found to be unconscious or thought to be suffering from myocardial infarction. Defibrillation success was defined as pulse resumption after ambulance treatment. Comparison of the success rates of two groups of patients were made. In group 1, patients were treated by ambulance equipped with a defibrillator, while in group 2, patients were treated by ambulance not equipped with a defibrillator. There were 772 patients in group 1 and 471 in group 2; 358 group 1 patients received defibrillation treatment. Thirty two of the group 1 patients regained pulse compared with 17 of the group 2 patients (8.94% versus 3.61%, p< 0.01). However, only 15 of the 32 group 1 patients were admitted to hospital, compared with 15 of 17 Group 2 patients (47% versus 88%, p<0.01). The fact that no increase in the number of patients admitted to hospital occurred, suggests that defibrillation therapy alone is insufficient to increase the salvage rate. Future paramedic training in Hong Kong should include endotracheal intubation, intravenous access and the administration of drugs.