In this study red ginseng was extracted with ethanol and then fermented by yeasts including Lactobacillus casei and Bifidobacterium longum. Fermented red ginseng extracts(FRGE) were found to be more effective antioxidants in vitro with regards to 1, 1-diphenyl-2-picrylhydrazyl(DPPH) radical scavenging activity than red ginseng extracts(RGE). In FRGE, the contents of ginsenosides Rb1, -Rb2 and -Rc were much lower than in RGE, however, the contents of ginsenosides 20(S)-Rg3, 20(R)-Rg3 and compound K were higher than RGE. FRGE was added to Yanggaeng(0, 5, 10, 15, 20%), and physicochemical and sensory evaluations of the Yanggaeng were conducted. The L and b values of Yanggaeng with added FRGE were decreased by increasing the ratio of FRGE, while the a value was increased. Sensory evaluations for, taste, color, flavor, texture and overall acceptability of Yanggaeng with addition of FRGE (10%) were applicable for improving the Yanggaeng product.