Doxorubicin (DOX) is the most widely used potent anthracycline antibiotic in the treatment of various solid malignant tumors. However, its effectiveness and clinical use are limited, especially due to dose-dependent cardiotoxicity (inability of the heart to pump blood effectively in the body) as a late effect. Limited studies have been conducted on the protective effects of high-intensity interval training (HIIT) on DOX-induced cardiotoxicity (DCT). The purpose of this research is to investigate the protective effect of HIIT on DCT by examining the expression of genes related to autophagy (Beclin1 and LC3II) and genes related to mitochondrial dynamics (fission proteins: DRP1 and FIS1 and fusion proteins: OPA1 and MFN2) in rat cardiomyocytes. Rats (N=24) were randomly divided into four groups: 1) Control, 2) DOX (20 mg/kg body weight), 3) HIIT (8 weeks, 7 sets of 4 minutes 80-90% VO2max isolated with 3-minute periods of 65-75% VO2max) and 4) HIIT+DOX. Evaluation of gene expression was done by RT-PCR test. The data were analyzed with ANOVA statistical tests and Tukey's post hoc test (α<0.05). Based on the results, DOX led to a non-significant increase in mitochondrial fission, a significant decrease in the autophagy process, a significant increase in OPA1, and a significant decrease in MNF2 (p<0.05). Also, HIIT alone and before DOX induction led to a significant decrease in fission, a significant increase in the expression of autophagy genes, a significant decrease in OPA1, and a non-significant increase in MNF2 (p<0.05). Therefore, HIIT could be a suitable protective strategy against DCT by inhibiting the changes made in the path of mitochondrial dynamics and autophagy.