Automatic junctional tachycardia is one of common atrial arrhythmia after open heart surgery which is often refractory to antiarrhythmic agents. We have experienced refractory automatic junctional tachycardia in two patients. In the first, it occured after cryosurgery for AV nodal reentry tachycardia and simultaneous dissection of a posterior septal bypass tract. In the second, it complicated the postoperative course of a patient who received intracardiac repair for double outlet right ventricle, ventricular septal defect, and pulmonary stenosis. Conventional therapy with atrial pacing, verapamil, digoxin, and electrical cardioversion were ineffective. Therefore, amiodarone was administered intravenously and it controlled automatic junctional tachycardia. The need for accurate and rapid diagnosis of this condition along with results of treatment are discussed.