A combination of hypertension and diabetes mellitus is known to be accompanied by higher oxidative stress than that observed in the individual disorder alone. The aim of this study is to measure the antioxidant vitamins vitamin C, vitamin E levels and lipid peroxidation status in hypertensive patients and diabetic hypertensive patients receiving vitamin supplements, insulin and lipid lowering drugs. The parameters where correlated with systolic and diastolic blood pressure of the patients. Lipid peroxidation was determined by measurement of Thiobarbituric reactive substance (TBARS) in the serum of patients. The antioxidant status was estimated by determining the levels of vitamin C and vitamin E in serum. A significant (p<0.05) increase in TBARS-MDA level was noticed in the hypertensive patients compared with the normotensive patients. Vitamin E status in hypertensive and diabetic patients were also significantly (p<0.05) lower than that of normotensive patients. However, a significant (p<0.05) decrease in TBARS-MDA levels was observed in the diabetic hypertensive patients compared with the hypertensive patients as well as normotensive patients while the vitamin C level significantly (p<0.05) increased in hypertensive and diabetic hypertensive patients. The present study showed that lipid peroxidation and oxidative stress are altered in hypertension and diabetic hypertension; there are reports that vitamin supplementation and lipid lowering drugs can reverse the effects of these alterations, however, there is no evidence to show that the reactive oxygen species initiated the alterations.