The objectives of this study were to investigate the status of vitamin D in Korean adolescents and to determine the association between serum 25-hydroxyvitamin D (25(OH)D) concentration and consumption frequencies of vitamin D food sources by season (June to November and December to May). The subjects were 1,579 adolescents aged 12-18 years participating in the 2008-2009 Korean National Health and Nutrition Examination Survey (KNHANES). Consumption frequencies of vitamin D food sources were estimated by using a qualitative food frequency questionnaire (FFQ). Thirteen food items were selected as vitamin D food sources including beef, egg, mackerel, tuna, yellow corvine, pollack, anchovy, mushroom, milk, yoghurt, ice cream, all fish and dairy products from the FFQ based on previous research. The data was analyzed using proc survey procedures. The deficiency (5.25-12 ng/mL), inadequacy (12-20 ng/mL) and sufficiency (> 20 ng/mL) proportions of serum 25(OH)D from June to November and December to May were 9.9%, 51.4%, 38.7%, and 39.4%, 51.4%, 9.2%, respectively. Mean serum 25(OH)D concentration was positively related to the consumption frequencies of mackerel, anchovy, all fish and milk. These results suggest high proportion (> 61%) of Korean adolescents were vitamin D deficiency or inadequacy, and serum 25(OH)D was associated with the consumption of vitamin D food sources including fish and milk.