Background: The coronary artery spasm (CAS) can be classified as angiographic focal or diffuse type spasm. This study was to investigate whether there are clinical and angiographic differences between focal or diffuse CAS induced by acetylcholine (Ach) provocation test. Methods: A total 1207 pts (606 men, Age; 58.12짹11.14 yrs) without significant coronary lesion underwent Ach provocation test. Ach was injected in incremental doses of 20, 50, and 100關g into left coronary artery. Focal CAS was defined when the length of significant narrowing is less than 20mm. Results: Significant CAS was documented in 668 pts (55.3 %) and classified as either Focal CAS (n=120) or Diffuse CAS (n=548). Baseline characteristics were similar between the groups. Although the rate of spasm to lower Ach doses (20 ug), Spasm severity and mean % stenosis were not different between groups, there were more chest pain, fixed lesion in the spasm segment and multivessel spasm in the pts with diffuse CAS. Conclusion: Documented diffuse CAS by Ach provocation test might be translated into more ischemic chest pain, mixed angina and significant multivessel spasm. This result may support that diffuse CAS is more responsible for the decreased vasomotility and coronary flow reserve than focal CAS. Special caution should be exercised for optimal medical management.