This study sought to compare everolimus-eluting stents (EES) versus Resolute zotarolimus-eluting stents (ZES) in terms of patient- or stent-related clinical outcomes in an "all-comer" group of patients with diabetes mellitus (DM) who underwent percutaneous coronary intervention. DM significantly increases the risk of adverse events after percutaneous coronary intervention. The efficacy and safety of second-generation drug-eluting stents, in particular EES versus ZES, in patients with DM have not been extensively evaluated. Patients with DM (1,855 of 5,054 patients, 36.7%) from 2 prospective registries (the EXCELLENT [Efficacy of Xience/Promus Versus Cypher in Reducing Late Loss After Stenting] registry and RESOLUTE-Korea [Registry to Evaluate the Efficacy of Zotarolimus-Eluting Stent]) who were treated with EES (n = 1,149) or ZES (n = 706) were compared. Stent-related outcome was target lesion failure (TLF), and patient-oriented composite events were a composite of all-cause mortality, any myocardial infarction, and any revascularization. Despite a higher risk patient profile in the ZES group, both TLF (43 of 1,149 [3.7%] vs. 25 of 706 [3.5%], p = 0.899) and patient-oriented composite events (104 of 1,149 [9.1%] vs. 72 of 706 [10.2%], p = 0.416) were similar between the EES and ZES in patients with DM at 1 year. In those without DM, EES and ZES also showed comparable incidence of TLF (39 of 1,882 [2.1%] vs. 33 of 1,292 [2.6%], p = 0.370) and patient-oriented composite events (119 of 1,882 [6.3%] vs. 81 of 1,292 [6.3%], p = 0.951), which were all significantly lower than in the DM patients. These results were corroborated by similar findings from the propensity score-matched cohort. Upon multivariate analysis, chronic renal failure was the most powerful predictor of TLF in DM patients (hazard ratio: 4.39, 95% confidence interval: 1.91 to 10.09, p < 0.001). After unrestricted use of second-generation drug-eluting stents in all-comers receiving percutaneous coronary intervention, both EES and ZES showed comparable clinical outcomes in the patients with DM up to 1 year of follow-up. DM compared with non-DM patients showed significantly worse patient- and stent-related outcomes. Nonetheless, overall incidences of TLF were low, even in the patients with DM, suggesting excellent safety and efficacy of both types of second-generation drug-eluting stents in this high-risk subgroup of patients.