Backgrounds and Objectives: Although an angina attack of vasospastic angina (VSA) can usually be relieved or controlled with nitrates and calcium channel blockers, there are some patients who cannot be controlled even by higher doses and combinations of these drugs. Cilostazol is a selective inhibitor of phosphodiesterase III that increases intracellular cAMP content. A stimulation of cAMP signal transduction increase coronary nitric oxide production. Therefore, we examined whether cilostazol improves angina symptoms in patients with uncontrolled vasospastic angina by conventional treatment. Methods: This study was conducted in a prospective, multicenter, non-randomized manner. The subject consisted of 21 patients (13 men, 57 짹 9 year-old) who were diagnosed with VSA and at least two angina attacks during the past 1 week despite of taking conventional medications such as calcium channel blockers and/or nitrates. They took cilostazol 100 mg twice daily for 1 week as an add-on the conventional medication. . The patients recorded the frequency of angina attack and wrote down the numeric rating scale of a ���severity of angina attack��� while taking conventional medications and taking cilostazol for two weeks, and also recorded a side effect of cilostazol. Using the Wilcoxon rank-sum test, we compared the changes in the scores of frequency and severity of angina attack before and after adding cilostazol. Results: After adding cilostazol on the conventional medications, there were 78.9% relative reduction of the score of angina intensity, and 73.5% of angina frequency (p<0.001) (Figures). There were four patients (19%) who were forced to stop cilostazol due to headache as a side effect Conclusion: Cilostazol appears to be an effective therapy in the uncontrolled VSA with conventional medical treatment. Further a prospective, randomized placebo controlled study will be needed to validate this result.