Background: Coronary artery spasm is known to be an important cause of myocardial ischemia. Compared with single-vessel spasm, multi-vessel spasm may induce more severe and prolonged myocardial ischemia. We assessed whether there are different angiographic and clinical characteristics between the multi-vessel spasm and single-vessel spasm induced by intracoronary acetylcholine (Ach) provocation test. Methods: Study population consisted of 1,207 patients (pts, male 56.4%, age 57.7짹11.1 years) who underwent coronary angiography with intracoronary Ach provocation test between Nov 2004 and Feb 2007. A total of 480 pts (39.8%) showed significant Ach-induced endothelial dysfunction. Clinical and angiographic parameters of multi-vessel spasm group (n=191, 39.8%) were compared with those of single-vessel spasm group (n=289, 60.2%). Results: Baseline characteristics were similar between two groups. Multi-vessel spasm group showed more typical chest pain and ST-T EKG changes during the Ach provocation test. Multi-vessel spasm group showed more vulnerable response to the lower Ach dose (20 to 50 µg). In addition, diffuse and severe spasms were more frequent in multi-vessel spasm group. Conclusion: Multi-vessel spasm group showed higher frequency of typical chest pain, ECG change during the intracoronary Ach provocation test and showed enhanced vasoconstriction response to lower Ach dose and diffuse, severe coronary spasm compared with single-vessel spasm group.