BACKGROUND Newer generation everolimus-eluting stents have improved angiographic and clinical outcomes compared with first-generation paclitaxel-eluting stents. However, it remains unclear whether there are differences in the safety and efficacy between everolimus-eluting and sirolimus-eluting stents in daily clinical practice. METHODS In two concurrent prospective registries, we prospectively included 2,876 consecutive patients undergoing percutaneous coronary intervention (PCI) with sirolimus-eluting stents at 41 centers, and 3,107 consecutive patients undergoing PCI with everolimus-eluting stents at 34 centers. The primary study outcome was a composite of death, myocardial infarction and target-vessel revascularization at 12-months. The rates of adverse outcomes are adjusted by means of Cox proportional-hazards methods ad propensity-score analysis (matching and covariate adjustment) to account for differences in patients��� severity of illness, angiographic, and procedural characteristics. RESULTS In overall 5,983 enrolled patients, the mean age was 64짹11 years and 67% of the patients were men. Thirty-three percent of the patients had diabetes, 52% presented with acute coronary syndrome, 16% had previous history of coronary angioplasty, and 52% had multivessel coronary disease. The mean ejection fraction was 59짹14%. Treated lesions of enrolled patients showed complex features representing real-world PCI situations; the proportions of diffuse long lesions were 62%, thrombus-containing lesions 8%, and ACC/AHA type B2 or C lesions were 76%, respectively. CONCLUSIONS The final results of the primary outcomes will be available at this-year meeting. This large-scale, prospective, ���real-world��� PCI registry data will provide critical information regarding the relative efficacy and safety of the unrestricted use of everolimus-eluting stents as compared to the use of early-generation sirolimus-eluting stents for coronary revascularization.