Background and Purpose There have been debates if glycemic control can affect cardiovascular events in DM patients. We tried to investigate the association between the preprocedural glycosylated hemoglobin(HbA1c) level and the occurrence of major adverse cardiovascular events(MACE) retrospectively in DM patients after PCI. Methods A total of 4853 patients from multicenter registry were included. 3113 patients didn���t have DM(non-DM group, M:F=2057:1056, mean age = 63 짹 11 yrs) and 1740 had DM. Of the patients with DM, 751 had a HbA1c < 7%(Low glycemic group, M:F= 471:280 mean age = 66 짹 10 yrs) and 989 had a HbA1c ��� 7%(High glycemic group, M:F= 567:422, mean age = 64 짹 10 yrs). MACE was defined as a composite of death, myocardial infarction and stroke. Results Low glycemic group showed lowest MACE free survival among 3 groups(Log rank, p = 0.001). On Cox multivariate regression analysis of DM patients, using the high glycemic group as a reference, low glycemic group was significantly associated with increased risk of MACE(Hazard ratio 1.479, 95% CI = 1.053-2.077, p = 0.024) adjusting age, sex, hypertension, ejection fraction, diseased vessel numbers and serum creatinine level. Conclusion Low baseline glycemic level might be a poor prognostic indicator in DM patients underwent PCI.