Dementia as a public health problem looms as an epidemic of the 21st century. The aging population places an increasing number of individuals at risk for dementia. It is predicted that the proportion of the population over 65 years will exceed 14% by 2022 in Korea. This paper aims at summarizing epidemiologic characteristics of dementia in the general population in Korea, which are essential to develop a preventive strategy to this dreadful disease. The prevalence of dementia has been estimated in several studies in Korea and was found to be around 9.5 to 13.0% among individuals aged 65 years and over, which appears a little higher than those reported in other countries. According to the etiologic subtypes, more than half of the cases are reported to be Alzheimer's disease (AD) in most studies, especially in studies conducted in rural areas. These results are similar to those reported in the western countries, with AD being more common. In Asia, it was expected that vascular dementia would be much more common than AD due to the high prevalence of cerebrovascular accidents. Women have a much higher prevalence rate than men in all studies, presumably due to the higher prevalence of AD among the oldest aged 80 and over. These phenomena may be related with the high rate of illiteracy and low level of education among women in this country. Further epidemiologic studies on the subtype and risk factors of dementia are necessary to develop a comprehensive strategy for prevention of this disease in Korea.