The purpose of this study was to determine the changes of MDA, glutation (GSH), Adenozine deaminase (ADA) and superoxidase dismutaze (SOD) levels with exercise training in obese middle-aged women (body mass index, MMI [greater than or equal to] 30.0). Twelve obese middle-aged women participated in this study. The descriptive statistics of some of the physical and physiological parameters of the participants were computed and the significance between the pre and post exercise levels of MDA, GSH, ADA and SOD values was determined. The results showed that the obesity and the acute exercise cause oxidative stress in women. Especially in obese women the increased levels of MDA and ADA levels may pose serious health problems. The obesity breaks down the anti oxidant defense mechanism of the body by effecting the GSH and SOD activities. That is why sudden and exhaustive exercises in obese people may have adverse effects on health. (Contains 2 tables.)