Objective: To explore the differences in serum lipidomic profiles between athletes diagnosed with nonalcoholic fatty liver disease (NAFLD) and those with nonalcoholic steatohepatitis (NASH), highlighting potential implications for athlete health and performance. Methods: A retrospective analysis was conducted on 40 athletes treated at our sports medicine clinic from January 2021 to December 2022. Participants were divided into two groups: those with NASH (n=18) and those with nonalcoholic simple fatty liver (NAFL) (n=22). Various metabolic and inflammatory markers were compared, including systolic and diastolic blood pressure, liver enzymes, lipid profiles, inflammatory cytokines (interleukin-6, tumor necrosis factor-alpha), and lipidomic profiles. Results: The study included 40 athletes, with no significant differences in gender, age, disease progression, or body mass index between the two groups. Liver stiffness measurements were significantly higher in the NAFL group. Both groups exhibited similar blood pressure and alanine aminotransferase levels; however, the NASH group showed elevated alkaline phosphatase levels. No significant differences were found in total cholesterol, triglycerides, or HDL cholesterol levels. The NASH group exhibited higher levels of inflammatory markers such as IL-6 and TNF-alpha and showed distinct lipidomic signatures compared to the NAFL group, with significant variations in certain phosphatidylcholines (PC), phosphatidylethanolamines (PE), and triglycerides (TG). Conclusion: The serum lipidomic analysis reveals distinct metabolic characteristics between athletes with NAFL and those with NASH, suggesting that specific lipid biomarkers may aid in differentiating these conditions in athletes. Understanding these differences is crucial for developing targeted interventions to manage liver health in athletes, optimizing their performance and recovery by addressing underlying metabolic disturbances.