BACKGROUND: Coronary artery spasm (CAS) is a major cause of variant angina in patients with chest pain without significant coronary stenosis. However, whether there are differences in the incidence of CAS according to the severity of underlying coronary artery fixed stenosis is limited. Methods: A total of 608 patients without significant coronary artery disease (CAD) who underwent the ergonovine (ERG) provocation test between January 2018 and December 2021 were enrolled. Significant CAS was defined as having≥70% of temporary narrowing by ERG test. Patients were divided into three groups, based on the presence of coronary artery stenosis: None group (n=456), mild group (30-49%,n=114) and moderate group (50-69%,n=38). Results: In patients with chest pain without significant coronary artery stenosis, mild stenosis was 18.8%, and moderate stenosis was 6.3% in the population. The baseline characteristics of the patients were worse in the mild and moderate group than in the None group, including age, hypertension, diabetes, and smoking habit. In the ERG test, CAS occurred in 44.4% (270/608) of the overall population. The incidence of CAS of the mild (55.3%) and moderate (52.6%) groups were higher than the None group (41.0%). Also, in the case of CAS occurrence, focal CAS (Length<20mm) was more frequent in the mild (14.3%) and moderate (30%) groups than in the no group (8.6%). CONCLUSIONS: In patients with resting chest pain without severe coronary artery stenosis, CAS was observed in a high proportion of nearly half by ergonovine provocation test. Moreover, the mild to moderate coronary artery fixed stenosis showed higher incidence of CAS and focal CAS than patients without fixed stenosis.