In this study we evaluated polyphenol contents, phytate contents, and antioxidant activities (DPPH radical and hydroxyl radical scavenging activity) in several soybean cultivars. The polyphenol contents of the cultivars ranged from 0.0446 mg/g to 0.0652 mg/g, with the highest level found in the WS82 cultivar, whereas and the lowest in Duyukong. The phytate content of the WS2906 cultivar was the highest at 22.28 mg/g whereas Duyukong showed the lowest level. $IC_50$ values (concentration of soybean extract exerting 50% scavenging of radicals) for DPPH radical and hydroxyl radical scavenging activity showed the highest in WS82. A positive correlation between DPPH radical scavenging activity and polyphenol contents was observed in the soybean cultivars, whereas not significant relationship between antioxidant activity and phytate content was found.