Oxidative stress is produced under diabetic condition and is likely involved in progression of pancreatic damage found in diabetes. In the present study, we examined possible protective effect of Achillea santolina L. (Compositae) against pancreatic damage in streptozotocin (STZ)-treated diabetic rats. Achillea santolina extract (ASE) is used by the traditional healers in many part of Iraq, as a hypoglycaemic agent. We evaluated the effect of ASE on blood glucose level, serum nitric oxide (NO) concentration and the oxidative stress status in rat pancreatic tissue. STZ was injected intraperitonealy at a single dose of 40mgkg(-1) to induce diabetes. ASE (0.1g/kgday) was orally administered to a group of diabetic rats for 30 consecutive days. Results showed significant reduction in the activities of superoxide dismutase (SOD), catalase (CAT) and pancreatic glutathione (GSH) levels in the diabetic rats compared to the control subjects. On the other hand, blood glucose level, serum NO, malondialdehyde (MDA), a marker of lipid peroxidation, protein oxidation indices including protein carbonyl (PCO) and advanced oxidation protein products (AOPP) were significantly elevated in pancreas of the diabetic group. Treatment with ASE reduced blood glucose level, serum NO, pancreatic MDA, PCO and AOPP. In addition, the content of GSH was restored to the normal level of the control group. Furthermore, ASE significantly increased CAT and SOD activities in ASE-treated rats. Based on our data, it can be concluded that Achillea santolina have a high hypoglycaemic activity and this may be attributed to its antioxidative potential.