We aimed to determine the proportion of frail patients among older adults with non-valvular atrial fibrillation (NVAF), characterize them and their use of anticoagulant therapy, and examine the association between frailty and clinical outcomes in a real-world setting using the ANAFIE Registry dataset. The target population consisted of more than 30,000 adults aged ≥75 years definitively diagnosed with NVAF by electrocardiogram. For this sub-cohort study, patients who answered the Kihon Checklist were registered prospectively. Patients were classified into robust, pre-frail, and frail groups based on the Kihon Checklist score. Of the 32,275 patients in the ANAFIE Registry, 2951 were enrolled in this subanalysis and responded to the Kihon Checklist: 959 (32.5%) patients were robust; 924 (31.3%), pre-frail; and 1068 (36.2%), frail. In the robust, pre-frail, and frail groups, respectively, the 2-year cumulative incidence rates of stroke/systemic embolic events were 2.4%, 3.3%, and 4.5%, (P = .025); all-cause death, 2.9%, 5.1%, and 13.7%, (P < .001); major bleeding, 1.5%, 1.2%, and 2.9%, (P = .029); and net clinical outcomes, 5.5%, 8.2%, and 17.1% (P < .001). Results were similar when comparing the robust+pre-frail vs frail groups. In multivariate analyses, cardiovascular death, all-cause death, and net clinical outcomes were significantly associated with frailty. In the robust+pre-frail vs frail groups, major bleeding was also associated with frailty. Frailty was associated with cardiovascular and all-cause death, net clinical outcomes, and major bleeding but not stroke or intracranial hemorrhage in older Japanese adults with NVAF. Copyright © 2022 The Authors. Published by Elsevier B.V. All rights reserved.