Supraventricular tachycardia caused by AV nodal dual conduction is usually re-entry tachycardia. We report a case of a 40-year-old man with incessant supraventricular tachycardia caused by simultaneous conduction via slow and fast AV nodal pathway. The patient was successfully treated with catheter ablation of slow AV nodal pathway, the treatment of choice of this form of tachycardia (when proper diagnosis is made). Analysis of previously published cases is discussed.