ABSTRACT: Background:Direct oral anticoagulants are the first-line drugs for anticoagulation therapy in nonvalvular atrial fibrillation (NVAF). However, a real-world, large-scale, clinical study on edoxaban has not been performed. Our ongoing postmarketing surveillance, ETNA-AF-Japan (Edoxaban Treatment in routiNe clinical prActice in patients with non-valvular Atrial Fibrillation; UMIN000017011), was designed to collect such data. Methods:Enrollment started on 13 April 2015 and ended on 30 September 2017. Eligible patients were those diagnosed with NVAF who were to receive edoxaban for the first time and provided written consent for study participation. Baseline patient characteristics and adverse events (AEs) were collected. Results:A total of 11 569 patients were enrolled. Data for 8157 patients in the first 3 months were analyzed. Mean age, body weight, creatinine clearance (CLcr), and CHADS 2 score were 74.2 ± 10.0 years, 60.0 ± 12.6 kg, 64.0 ± 25.6 mL/min, and 2.2 ± 1.3, respectively. Female patients, and patients with age ?75 years, body weight ?60 kg, and CLcr <30 mL/min constituted 40.7%, 52.4%, 54.6%, and 4.7%, respectively. Patients with paroxysmal, persistent, and permanent AF constituted 46.1%, 38.7%, and 15.1%, respectively. Most patients (85.3%) received dosages according to the prescribing information, and 90.8% continued the medication for 3 months. Bleeding AEs occurred in 3.29%, including major bleeding in 0.29%. Conclusions:The majority (90.8%) of patients continued medication and no significant safety concerns related to edoxaban were reported during the first 3 months of treatment. Clearer safety and efficacy profiles of edoxaban await data analyses after the 2-year follow-up period.