Background: Previous studies have suggested a pathophysiologic correlation between coronary spasm and atherosclerosis. Statin, a HMG-CoA reductase inhibitors, as a hypolipidemic drug has known to prevent atherosclerosis process. It was postulated that the administration of statin may decrease the incidence of acetylcholine (Ach)-induced significant coronary artery spasm (CAS). Methods: Between Nov 2004 and Feb 2007, a total 1199 patients (pts) presented with suspected variant angina underwent coronary angiography and Ach provocation test (20, 50 and 100 µg to left coronary artery). Pts under the statin pre-treatment were in 22% (263/1199 pts). Significant coronary artery spasm (CAS) was defined as focal or diffuse severe transient luminal narrowing (>70%). The Ach provocation test results and its associated parameters were compared between statin group (n=263 pts) and no statin group (n=936 pts). Results: Baseline clinical characteristics were similar between the two groups. The rate of (+) provocation test was higher in no statin group. Compared with statin group, some spasm related parameters including vulnerability to the spasm expressed by the (+) response to A1 dose and the incidence of severe stenosis of the spasm during the test were also higher in no statin group (Table). Conclusion: In our study, the pretreatment of statin before intracoronary Ach provocation test decreased the incidence of Ach-induced significant CAS and improved spasm-related parameters. Statin usage may have a beneficial role in managing clinically significant CAS by improving endothelial dysfunction and in its prevention.