BACKGROUND AND PURPOSE - : There is a scarcity of information on the epidemiology and natural course of moyamoya disease. The aim of this study was to investigate the nationwide epidemiological features of moyamoya disease in Korea, including incidence, prevalence, and survival. METHODS - : We used the data from nationwide, population-based Health Insurance Review and Assessment Service claims database and Rare Intractable Disease registration program, which includes physician-certified diagnoses based on uniform criteria for moyamoya disease from 2007 to 2011. Age-specific incidence and prevalence were calculated, and survival was examined using Kaplan-Meier method. RESULTS - : The total number of patients with moyamoya disease was 8154 in 2011, with a female-to-male ratio of 1.8. The incidence from 2007 to 2011 was 1.7 to 2.3/10, and the prevalence in 2011 was 16.1/10. In total, 66.3% of patients aged 0 to 14 years underwent surgery, whereas only 21.5% in the older than 15 years age group underwent surgery. The 1- and 5-year survival rates of adult patients were 96.9% and 92.9%, respectively, and of child patients were 99.6% and 99.3%, respectively. CONCLUSIONS - : The prevalence and incidence presented in this study are higher than those in previous studies. This study demonstrates that the burden of moyamoya disease in Korea is substantial.