Background: Long-term clinical outcomes of diabetes mellitus (DM) patients who underwent drug-eluting stent deployment has not well investigated. Methods and Results: A total of 2,050 cases were enrolled consecutively from 50 sites in Japan into the Cypher stent Japan Post-Marketing Surveillance (Cypher J-PMS) registry, and the 3-year outcomes of DM patients were analyzed. Subjects were divided into 2 groups based on the treatment of DM (insulin-treated diabetes (IT) group, n=207; and non insulin-treated diabetes (NIT) group, n=682). Major adverse cardiac event (MACE) rates in the IT group and the NIT group were 26.0% and 14.5% at 3 years, respectively (P<0.001). There were no significant differences in stent thrombosis rates (definite and probable by Academic Research Consortium (ARC) definition) (0% and 1.08%, respectively). Multivariate analysis suggested that hemodialysis and insulin-treated DM were independent predictors for MACE, and insulin-treated DM, hemodialysis and long lesions were strong independent predictors for target-lesion revascularization (TLR). Conclusions: Hemodialysis and insulin-treated DM were strong independent predictors of mortality and TLR in DM patients. These results might suggest that special attention to patients with hemodialysis and insulin-treated DM is warranted in the setting of sirolimus-eluting stent deployment for DM patients. (Circ J 2010; 74: 2592-2597)