The purpose of this study was to investigate the effects of dietary Chungkookjang (Korean fermented soybean) powder on blood glucose level, lipid profiles, antioxidant enzymes activities and histological changes in kidney of streptozotocin (STZ)-induced diabetic rats. Male Sprague-Dawley rats of three groups including nondiabetic group fed normal diet (NC), diabetic group fed normal diet (DC) and diabetic group fed Chungkookjang diet (DCH; 100 g/kg diet) were reared for 8 weeks. The serum glucose, triglycelide and total lipid levels in the DCH group were significantly lower (P<0.05) than the DC group. The renal xanthine oxidase, catalase and glutathione S-transferase activities in the DC group were significantly higher than the NC group. The xanthine oxidase, superoxide dismutase and glutathione S-transferase activities in the DCH group were significantly lower than the DC group (P<0.05). Tubular epithelial change, such as Armanni-Ebstein cells, was significantly reduced in the DCH group compared to the DC group. In conclusion, these results indicated that Chungkookjang supplement seems to be beneficial to correct the hyperglycemia and hyperlipidemia as well as to protect kidney against diabetic changes.