Background: Significant endothelial dysfunction or clinically evident vasospasm associated with drug-eluting stent (DES) has been reported; however, whether the DES associated coronary artery spasm (CAS) would predispose additional risk to mid to long-term major clinical outcome is not investigated yet. Methods: Among 1862 consecutive patients (pts) treated with DESs, 1010 pts underwent follow up coronary angiography (CAG) either due to recurrent chest pain or routine follow up during 12 months were enrolled. Among them, 160 pts with suspicious of CAS underwent the acetylcholine (Ach) provocation test by injecting incremental doses of 20, 50, 100 ug into the left coronary artery between March 2004 and April 2009. We compared the 12 months clinical outcomes of the pts with DES associated CAS (DES Spasm Group; n=112) with those of pts without CAS (No DES Spasm Group; n=48). Results: The baseline characteristics were similar between the two groups. The incidence of DES spasm was in 6.01% (112 pts/1862 PCI pts) in real-world setting. At 12 months, clinical outcome including the incidence of death, myocardial infarction (MI), repeat percutaneous coronary intervention (PCI), stenting of de novo lesion, major adverse cardiac events (MACE) and follow up CAG rate due to recurrent chest pain were similar between the two groups (Table). Conclusions : In our study, overall incidence of DES spasm was 6% which was confirmed by Ach provocation test. Pts with DES spasm didn���t exert any negative impact on major clinical outcomes compared with those of no DES spasm pts at least up to one year, suggesting relatively favorable prognosis with additional antianginal medical therapy.