Anesthesiologists are faced with a growing number of patients in need of cardiac pacing with symptoms of increasing complexity. Because intraoperative pacemaker malfunction can lead to sudden death, it is important for the anesthesiologists to possessthe information necessary to evaluate and treat such patients. On the other hand, torsade de pointes, a particular form of life-threatening polymorphic ventricular tachycardia, is known to be elicited in patients with cardiac pacemakers in the setting of abnormally long QT intervals, decreased heart rate and severe electrolyte disturbances, notably hypokalemia. We herein report a case of intraoperative torsade de pointes that was triggered by pacemaker malfunction-induced bradycardia in a patient with a VVI-type cardiac pacemaker, whose serum potassium and magnesium level were low preoperatively. (Korean J Anesthesiol 1999; 37: 164~167)