Abstract: The study was designed to investigate the effects of combined antioxidants of vitamins C [L-ascorbic acid] and E [DL-α-tocopherol] on endothelial inflammation biomarkers and oxidative stress in liver and kidney in streptozotocin (an i.p. single 40 mg kg-1 dose) induced diabetic rats. Concentrations of interleukin-6 (IL-6), Tumor Necrosis Factor-α (TNF-α), intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1(VCAM-1), lipid peroxidation product, thiobarbituric acid reacting substance (TBARS) and activities of glutathione peroxidase (GHP-Px), catalase (CAT) and superoxide dismutase (SOD) enzymes were compared in 3 groups of 10 rats each: control nondiabetic rats [group I], untreated diabetic rats [group II] and diabetic rats treated with vitamins C (200 mg kg-1day-1 i.p.) and E (100 mg kg-1day-1 i.p.) for four weeks [group III]). The rats in groups II had significantly (p<0.05) higher levels of blood glucose, Total Cholesterol (TC), triglycerides (TG), IL-6, TNF-α, ICAM, VCAM and TBARS than rats in group I. In addition, the rats in group II had significantly (p<0.05) lower activities of GHP-Px, CAT and SOD than group I. The treatment with vitamins C and E significantly (p<0.05) lowered blood glucose, TC, TG, IL-6, TNF-α, ICAM and VCAM levels by 36, 48, 34, 23, 23, 22 and 14%, respectively. Also, lowered TBARS levels and increased the antioxidant enzyme levels near to control values. The results verify the presence of oxidative stress in diabetes and suggest beneficial effects of combination vitamins C and E in combating the oxidative stress in this disease.