Background: polymer-free drug-coated stents provide superior clinical outcomes to bare-metal stents in patients at high bleeding risk who undergo percutaneous coronary intervention (PCI) and are treated with 1 month of dual antiplatelet therapy. Data on the use of polymer-based drug-eluting stents, as compared with polymer-free drug-coated stents, in such patients are limited. Methods: in an international, randomized, single-blind trial, we compared polymer-based zotarolimus-eluting stents with polymer-free umirolimus-coated stents in patients at high bleeding risk. After PCI, patients were treated with 1 month of dual antiplatelet therapy, followed by single antiplatelet therapy. The primary outcome was a safety composite of death from cardiac causes, myocardial infarction, or stent thrombosis at 1 year. The principal secondary outcome was target-lesion failure, an effectiveness composite of death from cardiac causes, target-vessel myocardial infarction, or clinically indicated target-lesion revascularization. Both outcomes were powered for noninferiority. Results: a total of 1996 patients at high bleeding risk were randomly assigned in a 1:1 ratio to receive zotarolimus-eluting stents (1003 patients) or polymer-free drug-coated stents (993 patients). At 1 year, the primary outcome was observed in 169 of 988 patients (17.1%) in the zotarolimus-eluting stent group and in 164 of 969 (16.9%) in the polymer-free drug-coated stent group (risk difference, 0.2 percentage points; upper boundary of the one-sided 97.5% confidence interval [CI], 3.5; noninferiority margin, 4.1; P = 0.01 for noninferiority). The principal secondary outcome was observed in 174 patients (17.6%) in the zotarolimus-eluting stent group and in 169 (17.4%) in the polymer-free drug-coated stent group (risk difference, 0.2 percentage points; upper boundary of the one-sided 97.5% CI, 3.5; noninferiority margin, 4.4; P = 0.007 for noninferiority). Conclusions: among patients at high bleeding risk who received 1 month of dual antiplatelet therapy after PCI, use of polymer-based zotarolimus-eluting stents was noninferior to use of polymer-free drug-coated stents with regard to safety and effectiveness composite outcomes. (Funded by Medtronic; ONYX ONE ClinicalTrials.gov number, NCT03344653.)