This study aims to compare the English vocabulary used in Korean high school English textbooks with the one in the College Scholastic Ability Tests (afterwards CSAT) administered in the years of 2009-2013 by using a concordance program, NLPTools, and to make a list of vocabulary used only in CSAT. The findings are as follows: First, when compared with Coxhead's (2000) Academic Word List, the 'Basic Words List' shows a conformity rate of 98.78%. Second, in terms of TTR (Type Token Ratio), there is no noticeable difference among the English textbooks. Third, in the respect of TTR, CSATs show higher figures, which means that CSATs' vocabulary is more difficult than that in the English textbooks and that for CSATs, annually each test has shown a gradual increase in the number of valid types. (This shows that more valid types to be learned are needed for the preparation of CSAT. Also the degree of difficulty in CSAT is getting higher.) Lastly, the higher level of the 208 words which occur only in CSATs illustrates that the gap between the vocabulary level of textbooks and that of CSAT needs to be reduced for normalization of public education.