A new surgical approach for implantation of the automatic implantable cardioverter defibrillator without thoracotomy was used in 12 patients, aged 46 to 72 years. Preimplantation arrhythmia was ventricular tachycardia in 7 patients and ventricular fibrillation in 5 patients. The mean ejection fraction was 19%. Six patients were at high risk for general anesthesia for a variety of medical problems, and 2 patients had had a previous cardiac operation. Epidural anesthesia was used in 8 patients without intubation. The surgical approach used a longitudinal epigastric extraperitoneal incision with access to the heart through an incision made in the central tendon of the diaphragm. Two patches and two epicardial sensing leads were placed in all patients. All patients but one could be defibrillated with 20 J or less. There was no operative mortality and minimal morbidity. There were two late deaths due to heart failure. Thus, the transdiaphragmatic approach provides an excellent exposure for automatic implantable cardioverter defibrillator implantation, avoids general anesthesia and thoracotomy, and can be used after a previous cardiac operation.