Background: Vasospastic angina(VSA) usually responds to conventional treatment with calcium channel blocker and nitrates. However, 5~30% of patients with VSA are refractory to those medications. Cilostazol is a selective inhibitor of phosphodiesterase 3(PDE3) and known to have some good effects for vasospasm such as vasodilation, inhibition of platelet aggregation and improvement of endothelial dysfunction. We investigated the applicability of cilostazol treatment for the vasospastic angina. Methods: Between December, 2008 and June, 2010, a total of 250 patients were diagnosed of variant angina in PNUYH. The uncontrolled case of 20 patients (8%) undergoing conventional medical treatment have been treated with additional cilostazol 100~200mg/day. We evaluated the effectiveness of cilostazol by means of clinical improvement which was simply checked their chest pain scale and clinical adverse effects before and after. We grouped the clinical response to cilostazol into three classes- Excellent, Good and No response. Definition of "Excellent" is almost resolved chest pain state ( from tolerable to no chest pain) and not necessary to additional another vasospastic medications, that of "Good" is some improvement of anginal chest pain but necessary to one more another vasospastic medications. That of "No response" is no chest pain improvement. Results: The 19 patients (95%) have a symptomatic improvement after receiving additional cilostazol. Of which 16 patients (80%) have a "Excellent" response to cilostazole treatment and the other 3 patients (15%) have a "Good" response. The only one patient (5%) has no response to cilostazol. Headache as adverse effect occurred in 4 patients (20%). Conclusions: Cilostazol appears to be an effective therapy in the uncontrolled VSA with conventional medical treatment. There seem to be an applicability of cilostazol treatment for the vasospastic angina. Further large prospective study will be needed to validate this result.