Introduction The present study purposed to investigate the effect of combined exercise and cardiac rehabilitation in mononuclear cells on ABCG1 gene expression in middle-aged men after coronary artery bypass graft surgery. Materials and Methods The statistical population of this study was 30 middle-aged male patients who previously had coronary artery bypass surgery. The subjects were randomly assigned into two groups: control (C; n=15), combined training (endurance and resistance training, ERT; n=15). Blood draws occurred prior to and after training sessions. After isolating monoclonal cell lines using ficoll and purifying mRNA, gene expression changes were done using Real-Time PCR. Data were analyzed by repeated sampling (SPSS software version 16). Results Eight weeks of combined exercise resulted in a significant increase in mRNA expression of the ABCG1 gene in ERT group compared to the C group. Conclusion Combined training as a part of the cardiac rehabilitation process in the patients undergoing coronary artery bypass graft surgery, by affecting the expression of the ABCG1 gene in the lipid metabolism, appears to augment the process of reverse cholesterol transfer.