Background: T Liver oxidative metabolism disorder is dependent on several factors that lead to liver diseases like non-alcoholic fatty liver disease. Our hypothesis was that the combination of high-intensity interval training (HIIT) and L-carnitine affects the expression of citrate synthase (CS), PGC-1α, and monocarboxylate transporter 1 (MCT1) in the liver of male Wistar rats. Methods: Thirty-two male Wistar rats were divided into four groups (n=8): control, L-carnitine (200 mg/kg/d, four weeks, IP), HIIT, and HIIT+L-carnitine (200 mg/kg/d, four weeks, IP). HIIT training was performed for four weeks (five days a week); then, the animals were anesthetized, and their liver tissues were extracted for real-time PCR to measure MCT1, PGC-1α, and CS. SPSS 22 software was used to analyze the data obtained in different groups, with P<0.05 considered statistically significant. Results: MCT1 expression significantly increased in the HIIT and HIIT+L-carnitine groups compared to the control group (P<0.001). PGC1α expression significantly increased in the HIIT+L-carnitine group compared to the control and L-carnitine groups (P<0.001). Also, PGC1α expression significantly increased in the HIIT group compared to the control group (P<0.001). Furthermore, CS expression significantly increased in all groups compared to the control group (P<0.001). Conclusion: HIIT exercise combined with L-carnitine supplementation increases the expression of MCT1, PGC-1α, and CS in the liver. Therefore, it seems that performing HIIT exercises and taking L-carnitine supplements can prevent the consequences of fat accumulation in the liver.