Background The capacity of circulating endothelial progenitor cells (EPCs) to repair vascular damage suggests that they may play a key role in maintaining homeostasis of the endothelium. The relationship between circulating EPCs and vasospastic angina (VSA) is incompletely understood. The aim of this study was to compare circulating levels of EPCs between patients with or without VSA. Methods Twenty-nine consecutive patients with chest pain were referred to our hospital due to suspected coronary artery disease. Coronary angiographies with acetylcholine provocation test were performed in all participating patients. VSA was confirmed in 19 patients and non-VSA in 10 patients. Peripheral blood were collected just after the angiography, and the absolute numbers of circulating EPCs such as CD34+/KDR+, CD34+/CD117+, CD34+/CD133+ were measured by flow cytometry. Moreover, smokers and non-smokers were compared within each group. Results Baseline characteristics were similar between the 2 groups. Absolute numbers of circulating levels of CD34+/KDR+ (168 짹 30 vs. 114 짹 24/𝜇L, P=0.047) and CD34+/CD117+ cells (271 짹 37 vs. 178 짹 23/𝜇L, P=0.029) were significantly greater in the VSA patients when compared with the non-VSA patients (figure 1). However, there was no significant difference in circulating levels of CD34+/133+ cells between the 2 groups (181 짹 43 vs. 174 짹 29/𝜇L, P=0.700). Circulating levels of CD34+/CD117+ cells were highest in the VSA patients with smoking when compared with the VSA patients without smoking and the non-VSA patients with or without smoking. Lipid profiles such as LDL cholesterol and inflammatory markers such as hsCRP and WBC counts were similar between the 2 groups. Conclusion This study demonstrated that circulating levels of CD34+/KDR+ and CD34+/CD117+ cells were significantly elevated in patients with VSA especially for smokers. Underlying molecular mechanisms need to be further elucidated.