The disturbances of contractile activity of rat neonatal cardiomyocytes under the influence of anthracycline antibiotics, in particular, doxorubicin, and the possibility of antioxidant correction of these disorders with curcumin were investigated. Also, the role of changes in the level of mitochondrial membrane potential in the contractile activity of cardiomyocytes was shown. It has been revealed that doxorubicin causes significant changes in all contraction parameters compared with control, namely: an increase in the frequency of spontaneous contractions, rhythm disturbance, a decrease in the amplitude and percentage of cell shortening, and an increase in the maximum rate of contraction and relaxation. Co-incubation with doxorubicin and curcumin caused a significant decrease in the frequency of spontaneous contractions (3 times), the restoration of their rhythm, an increase in amplitude (2-fold), the percentage of the cell shortening relative to the previous value, in the maximum contraction rate (1.8 times) and the rate of relaxation (by 16%), without significant changes in the duration of these processes compared with monoincubation with doxorubicin. In the study of mitochondrial membrane potential of neonatal cardiomyocytes by fluorescence method, a significant decrease in the intensity of doxorubicin-induced mitochondrial staining (1.7 times compared to control) was detected. Co-incubation of cells with curcumin and doxorubicin resulted in a significant rise in the fluorescence intensity of mitochondria (2.2 fold compared with doxorubicin alone).