The purposes of the study were to develop a questionnaire for dietary habit survey for Korean adults, unify the terms related to dietary habits, and establish the concept of dietary habits. In order to find out the common expression and definition for "dietary habits", 491 articles were analyzed. Many different expressions and 40 definitions for dietary habits were used. Thus, the Delphi method by 43 professionals on dietary habit research was applied to unify the terms and concepts of dietary habits into one. As for the results on terms related to dietary habit, the respondents recorded the highest percentage(90.7%) of selecting the term "dietary habits" and also the highest percentage(76.7%) of choosing "dietary habits" for English. The biggest percentage of the respondents chose "individual dietary behaviors repeatedly formed and habitualized under the social, cultural, and psychological influence in the group" as the concept of dietary habits. In an effort to develop a questionnaire on dietary habits, the contents of dietary habit questions in 391 articles were analyzed. There were 1,211 items that examined dietary habits, and 439 of them examined the dietary habits of adults. Of the 439 items, the most frequently asked question was "whether they have regular meals and how many regular meals they have a day"(35 items), which were followed by "whether they have meals a day and how many meals they have a day"(34) and "whether they overeat themselves and how many times they overeat themselves"(21) in the order. The analysis results of question content of items identified such problems as “there is confusion in the use of dietary habits, dietary behaviors, and dietary attitudes," “there are items on dietary behaviors and attitudes included in the items on dietary habits," "there are only a couple of items on dietary habits," and "only food frequency questions are examined in the dietary habit questionnaire." The problems with the examples of question items include too broad gaps of scale, improper scale organization, imbalance in scale organization, absence of base period, and partial omission of scale. The Delphi survey for the development of a questionnaire resulted in the first questionnaire of 31 items, the second one of 27 items, and the third one of 25 items. The validity of questionnaire items was tested with content validity ratios(CVR). The items whose CVR value was 0.29 or lower were eliminated or revised, because the minimum CVR value needed to test validity was 0.29. To test the reliability of questionnaire items, test-retest method was performed in 163 adults. According to the Kappa coefficient in the range of .314-.716, all of the 25 items were in the reliability scope. A survey was taken with 702 adults to finally revise and supplement the third questionnaire whose validity and reliability were tested. As a result, six items were considered to need revision: one item had additional explanations added, four items had the scales integrated, and the last one item had one of the examples eliminated. Through those processes, a questionnaire for adults'' dietary habit survey finally completed. The significance of the study lies in the development of the first questionnaire on dietary habits equipped with both validity and reliability in South Korea. The study also finds its significance in that it unified the terms related to dietary habits into one and established the concepts of dietary habits into one. If the questionnaire developed in the study is used by other researchers, it will become possible to compare the results of dietary habit researches by the areas, years, and subjects.