Abstarct: Introduction: Obesity is a mextabolic disease that has a negative effect on the health of the body and can also cause many other problems such as cardiovascular diseases, etc. The aim of this study is to investigate the effect of cuncurrent training on leptin levels and body composition in obese men. Method: The statistical population of this research was made up of people over 18 years old with a body mass index above 30 who had not participated in any regular exercise program for at least 2 years before the start of the research. and concurrent training in non-fasting conditions and control are divided. The training is about 180-190 minutes per week, which included 30 minutes of aerobic training and 30-40 minutes of resistance training and included 3 sessions per week. And the control group did not have any activity. 24 hours before the first training session and 24 hours after the last session, blood sampling was done from the antecubital antecubital vein in the laboratory by a laboratory science technician. Results: After analyzing the blood samples with special kits and testing the research hypotheses, the findings of this research showed. concurrent training had a significant effect on leptin levels in obese people in fasting and non-fasting groups. concurrent exercise had a significant effect on the percentage of body fat in fasting and non-fasting groups. Conclusion: Combination exercise can be used as a method in the treatment of obesity.