Background: Smoking has been known to be an independent risk factor of coronary morbidity induced by coronary artery spasm (CAS) but its detailed impact including duration and amount of smoking on coronary artery spasm is not clarified yet. We investigated the incidence of CAS according to smoking and smoking-related parameters. Methods: The study consisted of 306 patients (pts, Male 163, Age 56.1짹11.2 years) without significant coronary artery disease underwent acetylcholine (Ach) provocation test by injecting incremental doses of 20, 50 and 100 關g to left coronary artery. Significant CAS was defined as focal or diffuse severe transient luminal narrowing (>90%) with/without chest pain or ST-T change of EKG. Impact of conventional risk factors including smoking and smoking related parameters on CAS was analyzed. Results: Conventional risk factors of coronary atherosclerosis including hypertension, DM and hyperlipidemia were numerically higher in provocation (+) group but were not statistically different between two groups (Table). Only smoking itself was significantly higher in provocation (+) group whereas duration, amount and quit duration were not different between two groups. Further, smoking was not related to spasm severity and spasm type such as diffuse or focal spasm. Conclusion: Smoking itself appears to be an independent risk factor of CAS but smoking duration, amount and quit duration were not associated with CAS.