Platelet function testing could be useful when assessing the risk for bleeding during treatment with antiplatelet drugs. This has been indicated in several studies, including the Antiplatelet Therapy for Reduction of Myocardial Damage During Angioplasty–Bleeding (ARMYDA-BLEEDS) study, which demonstrated that testing with a point-of-care assay correlated with bleeding events after percutaneous coronary intervention. To standardize bleeding definitions, the Bleeding Academic Research Consortium (BARC) published a consensus report, which is in need of data-driven validation. Hence, the investigators conducted an observational, prospective, single-center study of 474 patients receiving clopidogrel and aspirin who underwent coronary angiography with or without percutaneous coronary intervention from October 2006 to May 2011. Platelet reactivity was measured with adenosine diphosphate–induced single-platelet function testing (Plateletworks) at the start of coronary angiography. The primary end point was the 30-day incidence of bleeding as defined by BARC and ARMYDA-BLEEDS. The aim of the present study was to investigate the relation between on-treatment platelet reactivity and the 30-day incidence of bleeding complications according to the BARC and ARMYDA-BLEEDS definitions. Patients in the first platelet aggregation quartile had a higher frequency of type 2 or higher BARC bleeding and ARMYDA-BLEEDS-defined bleeding <30 days after coronary angiography compared with the fourth quartile (16.9% vs 6.7%, p = 0.014, and 8.5% vs 1.7%, p = 0.016, respectively) and the third quartile (16.9% vs 7.7%, p = 0.031, and 8.5% vs 2.6%, p = 0.048, respectively). In conclusion, patients with low on-treatment platelet reactivity at the time of intervention had a significantly higher incidence of bleeding according to the BARC and ARMYDA-BLEEDS definitions <30 days after coronary angiography with or without percutaneous coronary intervention.