Elderly patients may have increased platelet reactivity and adverse events after percutaneous coronary intervention. Whether age is an independent predictor of worse outcomes after accounting for platelet reactivity is unknown. We sought to determine the relation between age and platelet reactivity on 2-year outcomes after percutaneous coronary intervention with drug-eluting stents (DES). ADAPT-DES was a prospective observational registry comprising 8,582 DES-treated patients. Patients were categorized with an age cutoff of 75 years. On-clopidogrel platelet reactivity was evaluated with VerifyNow P2Y12 testing. Multivariable Cox proportional hazards regression models were used to describe the relation between increasing age and 2-year clinical outcomes. Patients ≥75 old were more likely to be women and had more cardiovascular risk factors and more extensive coronary artery disease than younger patients. Residual platelet reactivity on-clopidogrel increased slightly with age (adjusted r = 0.05, p <0.0001). Age ≥75 years was associated with greater all-cause mortality (adjusted HR 1.64, 95% CI 1.25 to 2.15, p <0.001), myocardial infarction (adjusted HR 1.33, 95% CI 1.01 to 1.74, p = 0.04) and clinically relevant bleeding (adjusted HR 1.33, 95% CI 1.10 to 1.61 p = 0.003). In contrast, the risk of stent thrombosis was independent of age (adjusted HR 0.83, 95% CI 0.46 to 1.52, and p = 0.55). Considered as a continuous variable, age was directly related to clinically relevant bleeding, cardiac and all-cause mortality, was inversely related to stent thrombosis, and was not related to myocardial infarction. There was no significant interaction between age and on-treatment platelet reactivity for the risk of 2-year clinical outcomes. In conclusion, increasing age had a stronger association with the risk of death and bleeding than of thrombotic events. Despite being associated with older age, higher residual platelet reactivity did not modify the adjusted relative risks of ischemic and bleeding events associated with age.