We report the case of 67-year-old man with Brugada syndrome, in whom daily episodes of ventricular fibrillation (VF) occurred every early morning for 4 days. The episodes of VF were completely prevented by an oral administration of cilostazol, a phosphodiesterase inhibitor. This effect was confirmed by the on-and-off challenge test, in which discontinuation of the drug resulted in recurrence of VF and resumption of the drug again prevented VF. This effect may be related to the suppression of I(to) secondary to the increase in heart rate and/or to an increase in Ca2+ current (I(Ca)) due to an elevation of intracellular cyclic AMP concentration via inhibition of phosphodiesterase activity. This drug might have an anti-VF potential in patients with Brugada syndrome.