This article is a review on the value of antitachycardia pacing in patients with implantable cardiac-defibrillators (ICD). Antitachycardia pacing is highly effective in terminating monomorphic ventricular tachycardias, with a success rate of 80–90%. Which algorithm is used for termination seems to be of less importance, with respect to both efficacy and safety. Spontaneous episodes of ventricular tachycardia are slower and more easily convertible than those induced by programmed stimulation. It is thus possible that fine-tuning of the antitachycardia pacing algorithm, using induced episodes, is of limited value with respect to efficacy during follow-up. Prospective studies need to be performed to resolve this issue. Spontaneous monomorphic ventricular tachycardia can also occur in patients who are noninducible. Antitachycardia pacing should therefore also be considered for such patients. Inappropriate therapy, most often due to supraventricular arrhythmias, has been reported in up to 25% of patients. The sensitivity and specificity of algorithms developed to differentiate supraventricular from ventricular tachycardias still require validation. (Am J Cardiol 1996;78(suppl 5A):92–97)