Oxidative stress is currently suggested to play as a pathogenesis in the development of diabetes mellitus. There are many reports indicating the changes in parameters of oxidative stress in diabetes mellitus. The role of dietary management in diabetes mellitus is to provide a proper balance of total nutrients while meeting the special dietary needs of the patient. Complex carbohydrates and dietary fiber help to delay the absorption of glucose from the intestinal tract and minimize postprandial fluctuation of glucose. The present study was designated to evaluate the effect of special antidiabetic diet treatment upon oxidative stress parameters in the initial stages of the development of diabetes. The findings of the present study suggest that special diet formula useful for prevention of progressive hyperglycaemia in aged provoked diabetes in dogs could not restore the imbalance of cellular defence mechanism provoked by streptozotocin. Soluble fiber in the diet may also prolong gastrointestinal transit time, allow greater water absorption, and promote the production of short chain fatty acids which nourish the intestinal mucosa.