Edoxaban—a nonvitamin K antagonist oral anticoagulant (NOAC)— 60-mg and 30-mg once-daily dose regimens are noninferior vs well-managed warfarin for the prevention of stroke or systemic embolic events (SEE) with less major bleeding in patients with nonvalvular atrial fibrillation (NVAF). There are no published data from phase 3 clinical trials specifically evaluating the use of NOACs in elderly NVAF patients, especially those considered ineligible for available oral anticoagulants. The Edoxaban Low-Dose for EldeR CARE AF patients (ELDERCARE-AF) study is a phase 3, randomized, double-blind, placebo-controlled, parallel-group, multicenter study that will compare the safety and efficacy of once-daily edoxaban 15 mg vs placebo in Japanese patients with NVAF ≥80 years of age who are considered ineligible for standard oral anticoagulant therapy. A total of 800 patients (400 in each treatment group) are planned for randomization (1:1) to either edoxaban or placebo using a stratified randomization method with CHADS2 index score (2 points, ≥3 points) as a factor. The primary efficacy endpoint is the time to first onset of stroke or SEE. The net clinical outcome is the composite of stroke, SEE, major bleeding, and all-cause mortality. The primary safety endpoint is the incidence of major bleeding. The treatment period will continue until 65 patients with the primary effiacy events (ie, stroke or SEE) have been observed (2 to 2.5 year expected mean treatment period). The results of ELDERCARE-AF may provide clarity as to the efficacy and safety of edoxaban for the prevention of stroke or SEE in this high-risk population.