Three varieties of soybean, Chungtaik, Hillkong, and Endaedu which have been recommended to cultivate widely in Cheju Island, were chosen to study their amino acid metabolism in order to determine their nutritional values. 1) The total nitrogen contents of these soybeans were decreased in the order of Chungtaik, Hillkong, and Endaedu, indicating that the last variety is undesirable for a recommened formae even under a favorable condition of cultivation. The Hillkong variety may well be recommended for cultivation for a source of lipid rather than protein. 2) From analysis fo free amino acids, it was found that Hillkong contained normal amounto f vaious amino acids but Endae여 contained them in very abnormal fashion suggesting that an improved scheme of fertilization is necessary. Data from Chungtaik indicated it was excessively supplied with N fertilizer. 3) The amino acid contents of proteins extracted from these soybeans showed that Chungtaik contained less number of amino acids in its protein than the other two. The distribution of these amino acids appeared normal in Hillkong but quite irregular in Endaedu. In conclusion, both Chungtaik and Hillkong could be recommended for cultivation, the former as a protein source, the latter a lipid source of foods. Endaedu, however, may be liable to further research before it will be recommend for cultivation.