Background: the effects of dual antiplatelet therapy (DAPT) and triple therapy (TT: DAPT plus oral anticoagulation) in patients with atrial fibrillation (AF) undergoing percutaneous coronary intervention (PCI) regarding to CHA2DS2-VASc score remain undefined.We compare the effect of TT vs. DAPT in this setting regarding the CHA2DS2-VASc score. Methods and results: in a prospective multicenter registry, 585 patients (75.2% male, 73.2 ± 8.2 years) with AF undergoing PCI were followed up during 1 year. Of them, 157 (26.8%) had a CHA2DS2-VASc=1, and 428 (73.2%) had a CHA2DS2-VASc ≥2. TT was prescribed in 51.6% with CHA2DS2-VASc=1 and in 55.5% with CHA2DS2-VASc ≥ 2. Patients with CHA2DS2-VASc=1 receiving TT had a similar thromboembolism rate to those on DAPT (1.2% vs. 1.3%, P=0.73), but more total (19.5% vs. 6.9%, P=0.01) and a tendency to more major (4.9% vs. 0%, P=0.06) bleeding. However, patients with CHA2DS2-VASc ≥ 2 receiving TT had a lower thromboembolism rate (1.7% vs. 5.3%, P=0.03) and a trend towards more bleeds (21.8% vs. 15.6%, P=0.06), with an excess of major bleeding (8.4% vs. 3.1%, P=0.01). Rates of major adverse cardiac events (MACE) in both CHA2DS2-VASc subgroups were similar, irrespective of treatment. In a Cox multivariate analysis, TT was associated to major bleeding, but not with MACE. Conclusions: in patients with AF and CHA2DS2-VASc=1 undergoing PCI, the use of TT involves a high risk of bleeding without a significant benefit in preventing thromboembolism.