Atrial antitachycardia pacing was tested in 23 children and young adults. The majority of these patients had had operative repair of congenital cardiac defects and had both bradycardia and tachycardia. Pacemakers were usually implanted by the transvenous technique using bipolar leads. In each patient it was possible to find a tachycardia termination algorithm that successfully converted the tachycardia. In some patients very complex algorithms were necessary. In each patient it was also possible to find an algorithm that successfully differentiated the abnormal tachycardia from sinus tachycardia. Twelve patients required no antiarrhythmic drugs after pacemaker implantation, while 10 patients required one drug and one patient required two drugs. Eight of 23 patients had symptomatic tachycardias that required reprogramming the pacemaker to a different tachycardia termination sequence. Seven patients required reoperations, five for adapter problems and two for infection or erosion. Cardiac function improved in 15 of the 23 patients. Antitachycardia pacing is a viable option for management of tachycardias in children and young adults.