Background: Coronary artery spasm (CAS) is one of the important etiological factors for patients (pts) with chest pain but no coronary artery stenosis. Generally smoking and other factors were known the clinical risk factors for CAS. However, clinical aspects related to age on CAS have been seldom investigated and reported. We investigated whether there is any impact of old age on CAS and as compared with younger age by intracoronary acetylcholine (Ach) provocation test. Methods: A total 2954 consecutive pts without significant coronary artery lesion who underwent Ach provocation test by injecting incremental doses of 20, 50, 100 ug into the left coronary artery between March 2004 and April 2009 were enrolled. Significant CAS was defined as focal or diffuse severe transient luminal narrowing (>70%) with/without chest pain or ST-T change on ECG. the Ach provocation test results and its associated parameters were compared between the younger pt group (<50 years old, n=1044 pts, mean age; 41.13 짹 7.4 years) and older pt group (���50 years old, n=1910 pts, mean age; 62.06 짹 7.44). Results: Baseline clinical characteristics were similar between the two groups except that more male (58.3% vs. 42.0%, p<0.001) and smoker (38.9% vs. 24.3%, p<0.001) in younger patients group whereas more diabetes mellitus (16.3% vs. 6.0%, p<0.001), dyslipidemia (21.3% vs. 13.1%, p<0.001) and hypertension (54.2% vs. 32.6%, p<0.001) in older patients group. The rate of positive Ach provocation test was higher in the older pts group. Further, older pts group showed higher incidence of diffuse and multi-vessel spasm (Table). Conclusion: In our study, we found that old age predisposes towards a higher chances of significant CAS, diffuse and multivessel spasm as assessed with the intracoronary Ach provocation test. Special care should be emphasized in older age pts present with vasospastic angina.