Background: Acetylcholine (Ach)-induced coronary artery spasm (CAS) is associated with endothelial dysfunction in coronary artery. However, long-term clinical outcomes of Ach induced CAS is largely unknown. Therefore, we investigated the 12-month clinical outcomes of pts with CAS. Methods: A total of 1290 consecutive patients (pts) without significant coronary artery disease (CAD) underwent the acetylcholine (Ach) provocation test by injecting incremental doses of 20, 50, 100 ug into the left coronary artery were enrolled. Significant CAS was defined as focal and diffuse severe transient luminal narrowing (>70%) with/without chest pain or ST-T change on ECG. Pts were divided into two groups according to the Ach provocation test results: CAS Group, n=732, and No CAS Group, n=558. We investigated the Ach provocation test results, its associated parameters and 12 months clinical outcomes between the two groups. Results: The baseline clinical characteristics were similar between two groups. Out of 732 pts with CAS, 112 pts had history DES implantation (15.3%). Cumulative one-year incidence of mortality and myocardial infarction (MI) was 0.27% (2/732) and 0.14% (1/732), respectively in pts with significant CAS. At 12 months, two groups showed similar major clinical outcomes including the rate of death, MI, rate of repeat percutaneous coronary intervention (PCI), stenting of de novo leision, and follow up angiography due to recurrent chest pain (Table). Conclusions: In our study, pts with significant Ach-induced CAS had similar clinical outcomes at least up to 1 year including the rate of death, myocardial infarction, and the rate of stenting of de novo lesion compared with the control group who had (-) Ach provocation results with no significant CAD.