Background and Purpose: Selecting an ideal antithrombotic therapy for elderly patients with atrial fibrillation (AF) undergoing percutaneous coronary intervention (PCI) can be challenging since they have a higher thromboembolic and bleeding risk than younger patients. The current study aimed to assess the efficacy and safety of triple therapy (TT: oral anticoagulation plus dual antiplate- let therapy: aspirin plus clopidogrel) in patients > 75 years of age with atrial fibrillation (AF) undergoing percutaneous coronary intervention (PCI). Methods: A prospective multicenter study was conducted from 2003 to 2012 at 6 Spanish teaching hospitals. A cohort study of consecutive patients with AF undergoing PCI and treated with TT or dual antiplatelet therapy (DAPT) was analyzed. All outcomes were evaluated at 1- year of follow-up. Results: Five hundred and eighty-five patients, 289 (49%) of whom were > 75 years of age (79.6 ± 3.4 years; 33% women) were identified. TT was prescribed in 55.9% of patients at discharge who had a higher thromboembolic risk (CHA 2 DS 2 VASc score: 4.23 ± 1.51 vs 3.76 ± 1.40, p = 0.007 and a higher bleeding risk (HAS-BLED > 3: 88.6% vs 79.2%, p = 0.02) than those on DAPT. Therefore, patients on TT had a lower rate of thromboembolism than those on DAPT (0.6% vs 6.9%, p = 0.004; HR 0.08, 95% CI: 0.01 - 0.70, p = 0.004). Major bleeding events occurred more frequently in patients on TT than in those on DAPT (11.7% vs 2.4%, p = 0.002; HR 5.2, 95% CI: 1.53 - 17.57, p = 0.008). The overall mortality rate was similar in both treatment groups (11.9% vs 13.9%, p = 0.38); however, after adjustment for confounding variables, TT was associated with a reduced mortality rate (HR 0.33, 95% CI: 0.12 - 0.86, p = 0.02). Conclusions In elderly patients with AF undergoing PCI, the use of TT compared to DAPT was associ- ated with reduced thromboembolism and mortality rates, although a higher rate of major bleeding.