Compositional components such as isoflavone, protein, oil, fatty acid, and free sugar in Korean vegetable soybeans were examined with four cultivars including Hwaeomputkong, Keunolkong, Mirang, and Danmi 2. In the isoflavone, Mirang cultivar showed the highest content ($967.1{mu}g/g$), whereas Keunolkong was the lowest content ($535.9{mu}g/g$). The malonylglucosides were the predominant isoflavone type followed by the glucoside, aglycone, and acetyl glucoside forms, respectively. In the protein content, Hwaeomputkong was the lowest (41.7%) and Danmi 2 was the highest (45.9%). The oil contents were 11.5 to 21.2% and Mirang cultivar was the lowest. The fatty acid compositions of the oil extracts exhibited that linoleic acid was the highest (33.6-42.5%), followed by oleic, palmitic, linolenic, and stearic acids. Whereas, oleic acid ($46.7{pm}2.0%$) was more than linoleic acid ($33.6{pm}1.3%$) in Mirang cultivar. In the free sugar contents, Hwaeomputkong cultivar showed the highest level and sucrose ($5.52{pm}0.49%$) appeared to be most prevalent in vegetable soybeans.