The purpose of this study was to investigate food habits, nutritional knowledge, nutritional risk factors, health-related lifestyle, health status and dietetic therapy in Korean middle-aged and elderly outpatients taking supplements. A cross-sectional survey was conducted from July to December in 2001. Subjects were 1702 (male 731, female 971) age-related chronic disease outpatients aged over 50 years. Data was collected using a standardized Questionnaire by in-person interview and analyzed by SPSS system. The subjects with supplement had significantly lower nutritional knowledge, higher nutritional risk factors, undesirable lifestyle, and lower self-reported health status compared to those without supplement. However, the subjects with supplement had desirable (cod habits and more concern about health compared to those without supplement. Age-related chronic disease group with supplement had significantly undesirable food habits, lower nutritional knowledge and higher nutritional risk factors compared to control group with supplement. Age-related chronic disease group without supplement had significantly desirable food habits, higher nutritional knowledge, lower self-reported health status and higher stress compared to control group without supplement. Therefore, these results may provide basic information for proper supplement of Korean middle-aged and elderly outpatients.