OBJECTIVES: The burden of AF including stroke related costs is considered to remain substantial. The objective of this study is to assess the annual health care cost of AF in Japan. METHODS: A systematic literature review was conducted through searching MEDLINE and Ichushi-Web to identify evidence used in the analysis. We estimated the total number of patients with AF in Japan based on the prevalence rate of AF and the size of Japanese population. Total costs included treatment costs of major events associated with AF (stroke and bleedings), AF treatment costs and post-event long-term care costs. AF patients are assumed to be treated with warfarin, DOACs, or no treatment. Annual drug costs and outpatient costs were included and dosage of each drugs were correlated to relevant observational studies. The incidence rates of ischemic stroke (IS), hemorrhagic stroke (HS), intracranial hemorrhage (ICH) and gastrointestinal bleeding and average cost of each event were retrieved from the literature. Treatment costs of stroke and ICH were estimated by severity of disability. RESULTS: Annual number of IS, HS, ICH and gastrointestinal bleeding was estimated to be approximately 23,000, 8,500, 9,400 and 14,000, respectively. The annual medical cost and long-term care cost per patient was estimated to be JPY 104,000 - 145,000. The number of AF patients in Japan was 1.32 million in 2017, therefore, the nation-wide annual medical cost and long-term care cost of AF was estimated to be approximately JPY 137.5 billion - 191.4 billion over this period. CONCLUSIONS: The annual medical cost and long-term care cost of AF in Japan was high. As the prevalence of AF tends to be higher in the elderly population, the incidence of AF will further increase making the impact of the burden more enormous in Japan due to a large proportion of the population entering old age.