Introduction: Colorectal cancer is the leading cause of death in the world, and its frequency has been increasing. Coumarins have a strong inhibitory effect on different tumor cells, therefore their skeleton, as pharmacophore, is extremely important for the development of anti-tumor drugs. Research objectives: Test the effect of coumarin derivatives on the growth of normal epithelial cells and colorectal cancer cells in vitro. Determine the cell cycle change and the apoptotic path of treated cells. Materials and methods: The inhibitory effect of the derivatives has been determined by the MTT assay, performed on the three colorectal cancer cell lines (SW-60, HT-29 and CaCo-2) and the normal cell line (MDCK1). The cytotoxicity effect has been determined by measuring the LDH enzyme released in the cell medium. The alterations of the cell cycle have been monitored on the CaCo-2 cell line by the flow cytometry. The apoptosis pathway has been determined by measuring the membrane potential of the damaged mitochondria on the CaCo-2 cells. Results: The greatest cytotoxicity has been induced by the NS-48 and A-153 derivatives at the 10-4 M on all cell lines. The exposure of the CaCo-2 cells to NS-48 and A-153 derivatives has caused a mild increase of the cells in the G1 phase and the reduction of the cell number in the G2/M phase. The NS-48 and A-153 derivatives have caused a decrease of the mitochondrial potential and the depolarization of the membrane of the CaCo-2 cells. Conclusion: The coumarin derivatives reduce the cell growth of the tumor cells in a concentration depending manner and depending on the cell type. The alterations of the cell cycle and the reduction of mitochondrial potential in the cells treated by the coumarin derivatives have been observed.