Although patients suffering from atrial fibrillation have increased worldwide, detailed information about factors associated with bleeding during direct oral anticoagulant therapy remains insufficient. We studied 1086 patients for whom direct oral anticoagulants were initiated for non-valvular atrial fibrillation between April 2011 and June 2017. Endpoints were clinically relevant bleeding or major adverse cardiac and cerebrovascular events until the end of December 2018. Incidences of bleeding and thrombosis were 4.5 per 100 person-years and 4.7 per 100 person-years, respectively. Most bleeding events represented gastrointestinal bleeding. Multivariate analysis revealed initiation of anticoagulants at ≥ 85 years old as significantly associated with bleeding, particularly gastrointestinal bleeding, but not major cardiac and cerebrovascular events. Other significant factors included chronic kidney disease, low-dose aspirin and nonsteroidal anti-inflammatory drugs. For gastrointestinal bleeding alone, histories of gastrointestinal bleeding and malignancy also showed positive correlations, in addition to the above-mentioned factors. Clinicians should pay greater attention to the risk of gastrointestinal bleeding when considering prescription of anticoagulants to patients ≥ 85 years old with atrial fibrillation.