The purpose of this study was investigated hypoglycemic effects of fermented red ginseng extracts. We prepared non-fermented red ginseng extracts(R), fermented with Lactobacillus plantarum(RL) extracts, Saccharomycescerevisiae(RS) extracts, and L. plantarum mixed S. cerevisiae(RLS) extracts, examined composition of ginsenosides, SOD-like activity, and $alpha$-glucosidase inhibitory activity. Ginsenoside Re was highest contents in all extracts, second was ginsenoside Rc and then ginsenoside Rb1. Concentration of these ginsenoside was showed higher in RS than in other extracts. SOD-like activity and $alpha$-glucosidase inhibitory activity were shown higher in fermented red ginseng extracts than non fermented extracts. And activities of mixed fermentation extracts(RLS) higher than single fermentation extracts(RL, RS). Effects of blood glucose level, serum lipid profile and metabolic variables were evaluated in streptozotocin(STZ) induced diabetic rat. Experimental group was divided into 7 groups: normal control group(hereafter NC group), diabetes control group(DC group), positive control group treated with 50 mg/kg body weight of acarbose(PC group), treated with 300 mg/kg body weight of R, RL, RS and RLS extracts groups, respectively. Blood glucose level of DC group was maintained high level in all experimental period, but treated with red ginseng extracts groups was reduced the glucose level by R group 18.00%, RL group 28.07%, RS group 29.03%, RLS group 42.42%, respectively. The concentration of total cholesterol and triglyceride of fermented red ginseng extracts treated groups (RL, RS, RLS) was lower than non- fermented extracts group(R) DC and PC groups. The activity of ALT, AST in RLS treated groups were lower than other groups.