This study was done to investigate the antidiabetic and antioxidant effects of Cibotium barometz in Streptozotocin (STZ)-induced diabetic rats. Diabetes was induced by intravenous injection of STZ at a dose 45㎎/㎏.b.w. dissolved in citrate buffer(pH4.5). The ethanol extract of Cibotium barometz was orally administrated once a day for 7 days. The contents of serum glucose, triglyceride(TG) and total cholesterol were significantly decreased(p<0.05) in Cibotium barometz treated group compared to the those of STZ-control group, The content of glutathione(GSH) and activity of gluthathione-s-transferase(GST) were significantly increased (P<0.05) in Cibotium barometz treated group compared to the those of STZ-control group. andactivityes of catalase(CAT) and glutathione peroxidae(GSH-Px) were signiicantly decreased (P<0.05) in Cibotium barometz treated group compared to the those of STZ-control group. Also the content of hepatic glycogen and activities of glucose-phosphate dehydrogenase(G-6-PDH)and glucokinase(GK) were significamtly increased(p<0.05), but activity of glucose-6-phosphatase (G-6-Pase) was significamtly decreased (p<0.05) in Cibotium barometz treated group compared to the those of STZ-control group. These results indicated that ethanol extract of Cibotium barometz would have antidiabetic and antioxidant effects in STZ-induced diabetic rats.