Diabetes Mellitus (DM) is a syndrome characterized by chronic hyperglycemia and disturbances of carbohydrate, fat, and protein metabolism associated with absolute or relative deficiencies in insulin secretion and/or its action. Hypertension is common among patients with diabetes mellitus increasing their risks of cardiovascular morbidity and mortality. 72 white albino male rats weighting 250-300gm were included in this study. The rats were classified into six groups, each group include 12 rats. Group I (control group), group II (diabetic group receive STZ, 65 mg/kg B.W), group III (diabetic group receiving 600 mg/kg B.W vitamin E), group IV (diabetic group receiving 30 mg/kg B.W vitamin C), group V (diabetic group receiving 0.30 mg/kg B.W Capoten [ACE inhibitor] ), group VI (diabetic group receiving 250 mg/kg B.W L-arginine) Diabetic group showed increased blood pressure, increased cholesterol, triglyceride, LDL and decreased HDL, increased malondialdehyde and decrease in nitric oxide. Administration of vitamin E to STZ induced diabetic rats cause decrease in blood pressure, malondialdehyde, cholesterol, triglyceride, HDL, LDL and increase in nitric oxide. Vitamin C administration to STZ induced diabetic rats cause decrease in blood pressure, malondialdehyde, cholesterol, triglyceride, LDL and increased HDL. Injection of capoten cause decrease blood pressure, cholesterol, triglyceride and LDL while malondialdehyde level and nitric oxide remains as that of diabetic group. While administration of L-arginine decreased blood pressure, cholesterol, triglyceride, LDL and causes significant increase in nitric oxide level. But malondialdehyde level remain high as that of diabetic group. In conclusion, diabetes increased blood pressure and many factors contribute to the rise of blood pressure. It may be due to decrease in nitric oxide or change in renin – angiotensin – aldosterone system or oxidant stress or increased cholesterol, triglyceride, LDL or decreased HDL.