This study was performed to determine the levels of MMSE-K among the elderly people affiliated with long-term care insurance services in rural areas, and to reveal its association with related variables. The interviews were performed, during the period from March 1st, to May 31th, 2009, to 410 elderlies in rural areas. As a results, The prevalence of cognitive functions among all subjects were 80.5% of severe cognitive impairment, 11.7% of mild cognitive impairment, and 7.8% of normal. The prevalence of cognitive functions were lower according to the higher grade of long-term care insurance. And the prevalence of cognitive functions were lower in the group of lower educational level, unemployed, live alone, lower monthly income, bear for living expenses by sons and daughters and medical aid, lower visual acuity, with urinary incontinence, with amnesia, without regular exercise and lower frequency of going out than their respective counterparts. The hierarchial multiple regression analysis was used to reveal the explanatory powers of factors influencing on the cognitive functions level. Such factors as age, bear for living expenses, visual acuity, urinary incontinence, amnesia, regular exercise and grade of long-term care services were significantly influenced with cognitive functions. especially the factors of health status were significantly influenced with cognitive functions.