The optimal functioning of the liver is essential for athletic performance. It is necessary to maintain the liver’s enzymes at an optimal level so that liver cells can be protected from inflammation or damage. This study investigated the effects of a 12-week aerobic exercise program on the liver function of adult athletes. A pretest–posttest experimental design was used. A total of thirty healthy male athletes (football players) aged 21 to 24 years were recruited for this study and randomly and equally divided into the experimental group (EG) and control group (CG). The CG did not participate in any special activities. The EG performed an aerobic training program consisting of several exercises for 12 weeks. Evaluation of all participants in both groups was carried out before and after the intervention by measuring the blood levels of Alkaline phosphate, AST/SGOT, ALT/SGPT, Bilirubin Total/indirect/direct, Albumin, Globulin, and Total protein using the standard methods by collecting blood samples. There was a significant decrease (p< 0.05) in Bilirubin and globulin levels in the EG after 12 weeks of aerobic training sessions. However, there was no significant difference in alkaline phosphate, AST/SGOT, ALT/SGPT Total protein, and Albumin (p> 0.05) between both groups post-treatment. The 12 weeks of aerobic training used in the study can potentially improve the liver function of adult athletes.