The age-specific prevalence of dementia, its sex difference, and the relative prevalence of important types of dementia were studied in the elderly people in a Korean rural community. A two-stage approach was employed, involving screening and clinical assessment. The prevalence among individuals aged 65 and over was found to be 10.8%, with rates of 7.2% in men and 14.5% in women. The dementia was of the Alzheimer type in 60.0% of cases, multi-infarct dementia in 12.0%, mixed dementia of Alzheimer type and multi-infarct in 10.7%, alcoholic dementia in 8.0%, and others and unclassifiable in 9.3%. The prevalence of dementia of the Alzheimer type was significantly higher in women and rapidly increased with age in both sexes. The prevalence of multi-infarct dementia was not related to sex or age. Alcoholic dementia was identified only in men. These findings indicate that the prevalence of dementia in rural Korea is similar to that reported in Western countries and that the prevalence of dementia of the Alzheimer type in rural Korea is greater than that of multi-infarct dementia.