The present study was undertaken to evaluate the effect of Rhodiola sachalinensis root ethanol extract (RS), on the body weight, organ weight, plasma glucose and plasma lipid in diabetic rats caused by streptozotocin (STZ). The body weight decreased more slowly in the RS group than in the diabetic, and the food intake increased significantly in all diabetic groups. The food efficiency was very low in all diabetic groups, but increased significantly in the RS groups than diabetic control (p<0.05). In comparing the weight of organ, the weight of liver and kidney were increased in all diabetic groups than in the control, and decreased slightly in RS groups. The weight of heart and spleen were not different among all test groups. The glucose in serum was decreased significantly in the RS groups fed the RS for 4 weeks, compared to the diabetic control (p<0.05). Total cholesterol, triglyceride and atherogenic index (AI) in serum were significantly higher in diabetic control, compared to the normal (p<0.05), and decreased $16.7\%,;18.3\%;and;45.0\%$, respectively, in the RS fed $300;cal{mg/kg}$ of RS. HDL-cholesterol was increased slightly more in the $RS-300;cal{mg/kg}$, compared to diabetic control. These findings suggest that RS treatment has protective effect in diabetes.