Torsade de pointes (TdP) is a form of polymorphic ventricular tachycardia that is associated with prolongation of the QT interval. Although it occurs in many clinical settings, torsade de pointes is most commonly caused by drugs. The second generation antihistamines, including terfenadine and astemizole, have little sedation or other adverse effects on the CNS. They have been used widely to treat various allergic diseases, but it has been reported that overdoses or combinations with antifungal agents or macrolide antibiotics may lead to TdP. We report a case of TdP that occured during com-bination therapy of terfenadine and ketoconazole.