This study was conducted to compare the antioxidant activities of fermented soy products such as chungkukjang, meju and doenjang with soybeans. Total phenolic, flavonoids contents and antioxidative activities of the methanol extract of soy and fermented products were compared with specific reference to alpha-diphenyl-2-picryl-hydrozyl (DPPH) radicals scavenging effects, ferric /reducing power (FRAP), inhibition of conjugated diene formation and tyrosinase activities. Total phenolic and flavonoids contents increased in soybeans after fermentation. Fermented soy products also displayed enhanced antioxidative activities in comparison with the non-fermented soybeans. There were linear relationships between total phenolic and flavonoids contents and ferric reducing/antioxidant power of the samples. Overall, the fermented soy products showed a better antioxidant activity than soybeans. Among the 3 kinds of fermented soy products, chungkukjang, meju and deonjang, doenjang exhibited the highest levels of DPPH-free radicals scavenging activity, ferric /reducing power, inhibition of conjugated diene formation and tyrosinase activities. The fermented soy products with longer fermentation time demonstrated the higher antioxidant activities as well as higher total phenols and flavonoids in the order of doenjang > meju > chunghlkjang> soybeans.