This study included 30 obese patients, with BMI > 30, showing fatty liver by abdominal ultrasound (They were HBsAg & HCV Ab negative) and twenty non obese healthy age and sex matched subjects as a control group.We measured the level of serum thioredoxin which is an indicator of oxidative stress in various diseases and serum ferritin level which reflects oxidative stress and hepatic cell damage. Also we measured the degree of liver steatosis by CT as there is strong correlation between the CT attenuation values of the liver and the extent of fatty infiltration as measured by biopsy. The ratio of the CT attenuation value of the liver to that of the spleen (L/S ratio) was used for quantitative estimation of the hepatic fat content, with an L/S ratio of < 1being considered to represent fatty liver.In conclusion we found that there is an increase of the serum ferritin and serum thioredoxin levels in patients with NAFLD, and their levels tended to increase with the severity of the disease and its progression to NASH. So they may be used as a marker for detection of NAFLD and its severity