The antidiabetic effects of Rosa rugosa Radix were investigated in streptozotocine-induced diabetic rats. Research methods and procedure: In the present study, effects of oral administration of Rosa rugosa Radix extract(100, 250, and 500 mg/kg body wt.) for 28 days on the level of serum glucose, total cholosterol, triglycerides, cereatinine, aspartate amino transferase(AST) and alanine amino transferase(ALT) in normal and streotozotocine-induced diabetic rats were evaluated. Oral administrations of the Rosa rugosa Radix extract significantly decreased serum glucose, total cholesterol, triglyceride, AST, and ALT levels, while increased serum insulin and HDL-C in diabetic rats(p<0.05). The hypoglycemic effect of the Rosa rugosa Radix extract was more effective than normal group. It is concluded that the Rosa rugosa Radix must be considered as excellent candidate for future studies on diabetes mellitus.