We need the list and level of the type of affix to apply for selecting affixes for Korean vocabulary education. There are some criteria for affix selection; frequency, productivity, predictability and regularity of function and so on. Frequency is the number of words in which an affix occurs. Productivity is the likelihood that the affix will be used to form new words. Predictability is the degree of predictability the meaning of the affix. And regularity of function is the degree to which the affix attaches to a base of known form-class and produces a word of known. In this paper, frequency of derivational suffixes of Korean nouns is extracted from word-analyzed corpus including all kinds of elementary school textbooks. As a result of analysis based on corpus, we get the list of suffix like ‘-deul, -eum, -i, -nim, -ssik’ and ‘-jeok, -mul, -hyeong, -ja, -jang’ in order of frequency. The result of this paper can be applied for developing Korean textbooks for learners in aspect of derivative teaching and learning. Research on applying the result of measuring the frequency is to be followed as soon as possible. (The National Institute of the Korean Language)