Objective : This study wascarried out to understand the effect of Sopyung-tang (SPT) on blood glucose & antioxidant enzyme activities in streptozotocin-induced diabetic rats. Methods : SD rats were separated into three groups, each with 20 rats. Except the normal group, the other two groups were intra-peritoneally injected with streptozotocin 6mg/kg. The experimental group was treated with SPT extract 500mgkg/day for 4 weeks. The normal and control groups were treated with saline 500mg/kg/day for 4 weeks. Changes of plasma glucose level and body weight were observed. After4 weeks, liver and kidney weight, antioxidant enzyme activities, and survival rate were observed with histological changes on liver, kidney and pancreas. Results : In the experimental group, body weight and survival rate increased, while plasma glucose level decreased significantly. Liver and kidney weight, XOD activity decreased in the experimental group compared to the control. GSH-px and CAT activities andinsulin-immunoreactive granules in ${eta}-cells$ increased significantly in the experimental group compared to the control. Conclusions : This study shows that SPT might be effective for treatment of diabetes and its complications, as well as reduction of oxidative stress.