OBJECTIVES: Atrial fibrillation (AF) is a chronic, progressive disease characterized by uncoordinated atrial activation involving a rapid and irregular heartbeat (Fuster et al. 2006). The prevalence of AF is <1% in adults <55 years old, but increases to as much as 10% by age 80 (Go et al. 2001). The purpose of this study was to forecast the incidence of AF in selected countries for 2015, 2020 and 2025 based on predicted prevalence. METHODS: The prevalence of AF in Brazil, Canada, China, India, the United Kingdom and United States (US) was forecasted based on prevalence rates identified via a literature search and 2010 estimates of AF prevalence.  Population forecasts for the selected countries were taken from United Nations Department of Economic and Social Affairs forecasts. The adult population was adjusted for the percentage of the population with access to health care. The model assumed current age-adjusted prevalence rates would remain constant through 2025. One-way sensitivity analysis was performed for the health care accessible population and the country forecasted population. RESULTS: The prevalence and economic burden is forecasted to increase from 0% to 2% per year in the selected countries. In 2025, the prevalence and economic burden ranged from 282,000 and 245 million Lira in Turkey to 2.68 million and $17 billion in the United States. The burden is reported in 2010 local currencies. Sensitivity analyses revealed that prevalence in developing countries were most affected by health care accessibility. In developed countries, prevalence was most affected by forecasted population growth. CONCLUSIONS: The prevalence of AF in selected countries was forecasted to grow substantially in both developing and developed countries.  As the world’s population ages and health care becomes more accessible, the economic burden of AF will continue to rise as well.