Trasodone, a second generation antidepressant, has been shown to equal standard tricyclics in clinical efficacy while causing significantly fewer cardiac side effects. Although clinical trials have demonstrated a relatively safe arrhythmogenic profile, trasodone has been implicated in the pathogenesis of ventricular arrhythmias. This report describes a patient in whom the administration of trasodone in addition to previously well-tolerated long-term amiodarone therapy was associated with a marked prolongation of the QT interval and polymorphous ventricular tachycardia. Caution in the concurrent use of trasodone and other medications known to cause QT prolongation and polymorphous ventricular tachycardia is recommended.