The well known animal models are not satisfactory in reproducing the essentials of human type 2 diabetes. A recent experimental model successful in producing type 2 diabetes in rats is induced by neonatal streptozotocin (STZ) administration. In the present study, diabetes was accomplished in rats by the intraperitoneal injection of STZ (65 mg/kg) on the second day of birth. Blood glucose levels were monitored until the fourth month. At the fourth month, diabetic rats were divided into three groups (glucose levels > IOmmol/L). The first group (n = 8) did not receive any medication, glibenclamide and glipizide were administered respectively to the second group (n = 8; 5 mg/kg bw) and third group (n = 8; 5 mg/kg bw) for a one month period. In order to observe the antioxidant effects of glibenclamide and glipizide, the levels of Malondialdehyde (MDA) a lipid peroxidation marker, and the activity of catalase (CAT), an antioxidant enzyme, were determined in various tissues in all of the diabetic groups compared to the controls (n = 8, glucose levels similar to 6 mmol/L).