The hypoglycemic effects of germinated rough rice extract in streptozotocin (STZ)-induced diabetic rats were investigated. Weight gain was significantly lower in the diabetic groups than in the normal control (NC); however, they were higher in the 1% and 3% diabetic groups given germinated Goami2 rough rice extract (DM-3%GGRRE) than in the diabetic control (DC). While food intake in all diabetic groups was significantly higher than that of the NC, there was no significant difference among all diabetic groups. The weight percentages of liver and kidney in all diabetic groups were significantly higher than that of the NC. In terms of blood glucose, the diabetic group showed about a three times larger value than the normal group. Moreover, in the 3% germinated rough rice extract group, the blood glucose level became lowered. The levels of alanine transaminase, aspartate transaminase, blood urea nitrogen, creatinine phosphokinsae, and creatinine increased in general with the induction of diabetes using STZ; however, the 3% GGRRE-treated group displayed a significant decrease in these levels compared to the diabetic group. The results show that the 3% GGRRE, rather than the 1% GGRRE, was considerably more effective at reducing blood glucose and improving impaired glucose tolerance, suggesting the germinated rice extracts may play a role in preventing liver and kidney damage.