BACKGROUND/OBJECTIVES: Eating-out among Korean people has become an important part of modern lifestyle due to tremendous growth of the food service industry and various social and economic changes. This study examined trends in meal patterns and meal sources while eating-out among Korean adults aged 19 years and older. SUBJECTS/METHODS: Data were from the 1998-2012 KNHNES (Korea National Health and Nutrition Examination Survey) by the 24-hour dietary recall method. This study included 55,718 adults aged 19 years and older. For analysis of eating-out frequency, data were categorized by source of meals and serving place. RESULTS: Average frequency of meals consumed away from home increased from 1998 to 2012, although it remained lower than that of meals at home. In addition, male, unmarried, employed, higher educated, and high income individuals more frequently consumed meals away from home. Moreover, sodium intake while eating-out significantly increased from 2,370 mg in 1998 to 2,935 mg in 2012. Lastly, percentage contributions of daily total protein intake, fat intake, and sodium intake from eating-out increased to more than half (53-55%) in 2012 compared with 47-48% in 1998. CONCLUSIONS: As eating-out has grown in popularity, greater recognition of public health and nutritional education aimed at promoting healthy food choices is needed. In addition to developing consumer education for overall healthier eating patterns, individuals who are younger, unmarried, higher educated, and males are especially at risk and require attention.