Treatment of resuscitated patients with implantable cardioverter defibrillators has become increasingly more common as a method for the prevention of sudden cardiac death. Major complications such as perioperative death (incidence 2% to 8%), infection (2% to 11%); and lead-related problems (3% to 27%) have been described in previous trials. In our experience with 140 patients, problems were related to leads (n = 11), the device (n = 2), pacing (n = 1), sensing (n = 13), and defibrillation function (n = 5). Additional problems that occurred during the perioperative period included infection (n = 11), hematoma, and seroma (n = 2). Thrombus formation along endocardial leads was observed in 13 of 62 (21%) patients. Different arrhythmias (n = 10), such as sinus tachycardia, atrial fibrillation, and nonsustained, slow or incessant ventricular tachycardia with shock delivery, were also detected. Surgical management (predominantly for the major problems) was used in 31 (48%) patients, drug treatment in 25 (39%), and reprogramming of the device in 24 (38%) patients. All of these problems can result in an increase in mortality rates. This article provides an overview of the complications of cardioverter defibrillator treatment and is based on both published data and our series.