This study was performed to investigate the relationship between diet quality and food cost and identify the effects of food cost on healthy diet among Korean adult. Among the subjects of 2001 National Health and Nutrition Survey 1,641 men and 1,765 women aged from 30 to 49 years were selected and their information of dietary intakes, socio-demo-graphic information, and anthropometric data were analyzed. For the analysis, subjects were classified to quartile based on their daily food cost. Food guidelines provided by Korean Nutrition Society was regarded as a model of healthy diet. Subjects in the lowest quartile of food cost consumed inadequate amount of food from all food categories of the guidelines. Many subjects in the highest quartile not only satisfied the recommended amount of the Food Guide but also seemed to overeat high energy density foods. Even in the highest quartile, about 90% of subjects did not satisfied recommended amount of dairy products. According to the calculated cost of healthy diet, the average cost did not seem to be more expensive than the current mean food cost of the subjects, and most cost-sensitive food intake was observed in the meat fish beans eggs category. The implications of study results were: 1) all the high cost diets did not indicate the high quality of diet, 2) most practical matter of healthy diet in low income group seemed whether they could afford the expense of meat and fish, 3) nutrition education was required to most subjects for healthy diet.