Oxidative stress is suggestive to contribute to pathological process in many diseases e.g. cancers, atherosclerosis and diabetes.Diabetes mellitus is a disorder characterized by hyperglycemia due to an absolute or relative deficiency of insulin and or insulin resistance. Long-term exposure to oxidative stress is strongly implicated in the pathogenesis of diabetic retinopathy. Polymorphic genes of detoxifying enzymes are implied in the development of DR. Homozygous gene deletion of GSTM-1 result in lack of enzyme activity. This study describes that genetic variation in GSTM-1 gene may influence susceptibility to retinopathy in patients with type II diabetes mellitus.