As the population ages, health problems of the elderly, including functional disorders and cognitive impairment, have become some of the most important social issues in Korea. The purpose of this study is to discover the rate of prevalence and factors related to dementia among the elderly in Jeju Province. 2405 elderly in Jeju Province were interviewed, using a questionnaire consisting of sociodemographic characteristics： health behavior, quality of life, and MMSE-K. Prevalence of dementia was 9.4%(11.7% of females, 4.1% of males). Factors related to dementia, analyzed by multiple logistic regression, were age, working status, subjective health status, social support, and subjective economic status. In community health care for the elderly, factors relating to dementia have to be considered. When planning community health care, priority should be given to the elderly who： need care but live alone； lack social support； have a low standard of living； believe they are not in a good state of health； or whose life satisfaction is low.