Oxidative stress plays a major role of free radicals generation disproportionately in diabetes mellitus by glucose oxidation, nonenzymatic glycation of proteins, and the subsequent oxidative degradation of glycated proteins. Abnormally high levels of free radicals and the simultaneous decline of antioxidant defense mechanisms can lead to damage of cellular organelles and enzymes, increased lipid peroxidation, nitric oxide level and development of insulin resistance. These consequences of oxidative stress can promote the development of complications of diabetes mellitus. Changes in oxidative stress biomarkers, including catalase, glutathione peroxidase, lipid peroxidation, nitrite concentration and their consequences, are discussed in this research article. Biochemical studies were carried out in 10 diabetes patient whose age range from 45-55 years. For control data, 10 individuals in the same group (45-55 years), socio-economic status and who were not suffering diabetes mellitus as a control groups.