Background: In patients with coronary vasospastic angina, coronary atherosclerosis gives rise to coronary vasospasm. Inflammatory markers are elevated as well as peripheral monocyte count was increased in these patients. We have postulated that peripheral leukocyte count and differential count are clinically feasible in making a diagnosis of patients with vasospastic angina. Methods: We examined clinical data of 144 patients who underwent intracoronary ergonovine test between January 2002 and December 2004. Based on the presence of spasm, we divided patients into two groups: Group I (patients with spasm) and Group II (those without spasm). Between the two groups, we compared lipid profiles and inflammatory markers. Results: Overall, 72 patients were positive to intracoronary ergonovine test with a positive rate of 50%. There were no significant differences in the levels of serum lipid, hsCRP and ESR between the two groups. WBC and monocyte count were significantly higher in Group I than with Group II (p=0.035 and p<0.001). Gensini���s score was also significantly higher in Group I than Group II (2.2짹2.88 vs. 0.5짹1.03) (p<0.001). Multivariate analysis showed that peripheral monocyte count and Gensini���s score were independent factors affecting coronary vasospastic angina (p=0.047 and p=0.018). According to a receiver operating characteristics (ROC) curve analysis, the area under curve (AUC) of monocyte count was 0.738, greater than that of neutrophil count (0.577, p=0.007) and WBC count (0.572, p=0.003). The cut-off value of monocyte count was 530/mm3, in which the sensitivity and specificity were 64% and 76%, respectively. Conclusion: Peripheral monocyte count will be clinically feasible in making a prompt diagnosis of patients who are suspected of having vasospastic angina.