BACKGROUND The roles of anticoagulation alone or with an antiplatelet agent after transcatheter aortic-valve implantation (TAVI) have not been well studied. METHODS We performed a randomized trial of clopidogrel in patients undergoing TAVI who were receiving oral anticoagulation for appropriate indications. Patients were assigned before TAVI in a 1:1 ratio not to receive clopidogrel or to receive clopidogrel for 3 months. The two primary outcomes were all bleeding and non-procedurerelated bleeding over a period of 12 months. Procedure-related bleeding was defined as Bleeding Academic Research Consortium type 4 severe bleeding, and therefore most bleeding at the puncture site was counted as non-procedure-related. The two secondary outcomes were a composite of death from cardiovascular causes, non-procedure-related bleeding, stroke, or myocardial infarction at 12 months (secondary composite 1) and a composite of death from cardiovascular causes, ischemic stroke, or myocardial infarction (secondary composite 2), both tested for noninferiority (noninferiority margin, 7.5 percentage points) and superiority. RESULTS Bleeding occurred in 34 of the 157 patients (21.7%) receiving oral anticoagulation alone and in 54 of the 156 (34.6%) receiving oral anticoagulation plus clopidogrel (risk ratio, 0.63; 95% confidence interval [CI], 0.43 to 0.90; P = 0.01); most bleeding events were at the TAVI access site. Non-procedure-related bleeding occurred in 34 patients (21.7%) and in 53 (34.0%), respectively (risk ratio, 0.64; 95% CI, 0.44 to 0.92; P = 0.02). Most bleeding occurred in the first month and was minor. A secondary composite 1 event occurred in 49 patients (31.2%) receiving oral anticoagulation alone and in 71 (45.5%) receiving oral anticoagulation plus clopidogrel (difference, −14.3 percentage points; 95% CI for noninferiority, −25.0 to −3.6; risk ratio, 0.69; 95% CI for superiority, 0.51 to 0.92). A secondary composite 2 event occurred in 21 patients (13.4%) and in 27 (17.3%), respectively (difference, −3.9 percentage points; 95% CI for noninferiority, −11.9 to 4.0; risk ratio, 0.77; 95% CI for superiority, 0.46 to 1.31). CONCLUSIONS In patients undergoing TAVI who were receiving oral anticoagulation, the incidence of serious bleeding over a period of 1 month or 1 year was lower with oral anticoagulation alone than with oral anticoagulation plus clopidogrel. (Funded by the Netherlands Organization for Health Research and Development; POPular TAVI EU Clinical Trials Register number, 2013-003125-28; ClinicalTrials.gov number, NCT02247128.