Aim: Obesity has adverse consequences on immune system, causing immunosuppression and thus, obese individuals have higher incidence of infections and certain types of cancer. The aim of this study was to compare changes in leptin and selected immune system response after moderate and intense aerobic exercise training in obese subjects. Method: Forty obese male subjects, their age ranged between 35 to 55 years old. The subjects were included into 2 equal groups; the first group (A) received moderate intensity aerobic exercise training. The second group (B) received high intensity aerobic exercise training for 3 months. Result: There was a 6.7% and 9.2% reduction in mean values of body mass index (BMI) and Leptin respectively and 4.8% increase in mean values of immunoglobulin G (IgG) in group (A). While , there was a 3.4% and 3.7% reduction in mean values of BMI and Leptin respectively and 2.3% increase in mean values of IgG in group (B) . The mean values of BMI and Leptin were decreased and IgG was increased significantly in group (A) and group (B).Also; there was a significant difference between both groups after treatment. Conclusion: Moderate intensity aerobic exercise training on treadmill is appropriate to improve BMI, leptin and IgG in obese male patients.