Nutrition is one of the factors influencing cognitive functions. But, the role of nutrition on cognitive functions within the elderly is recognized to a lesser degree. The aim of this academic endeavor was to analyze the affiliation between nutritional status and cognitive functions of the elderly in Korea. 316 subjects, of 114 male and 201 female aged above 65 years, were gathered from university hospital clinics, Elderly Welfare Centers, and Health Welfare Centers located in the district of Seoul, Gyeonggi province, and Incheon in Korea. The cognitive function was tested by the Korean-Mini Mental State Examination (K-MMSE) questionnaire. Nutrition intake was assessed by a 24-hour recall, a food frequency questionnaire (FFQ). Nutrition adequacy and quality were assessed by the Nutrition Screening Initiative (NSI) checklist, the nutritional adequacy ratio (NAR), and the mean adequacy ratio (MAR). The elderly with normal cognitive function status displayed significantly higher levels of calcium, riboflavin, thiamin, folate, vitamin C, vitamin E, vitamin B6, phosphorous, potassium, iron, niacin, zinc, animal fat, animal protein, polyunsaturated fatty acids, total protein, vegetable oil, vegetable protein, fiber than levels of the elderly with moderate cognitive impairment. The K-MMSE score positively correlated with of high consumption of pork, white radish, sea mustard, tomato, tangerine, grape, apple, and ice cream, and K-MMSE was negatively associated with high intake of potato, anchovy, fish cake, and mushroom. The findings suggest that nutritional status is affiliated with cognitive function within the elderly of Korea. The consumption of variety of foods and nutrients ensures adequate cognitive function in the Korean elderly.