Breast cancer is the major leading cause of death from cancer among women. Given the drug resistance seen during the treatment of this disease, it is very important to identify new therapies and new anticancer drugs. Some studies indicate the cytotoxic effects of cyanidin 3-glycoside (C3G). Therefore, this study aims to evaluate the anticancer effect of C3G in the treatment of the MCF-7 cell line. In this study, the MCF-7 cell line was treated with different concentrations of C3G for 24 and 48 h. Assessment of cell death was performed by MTT assay. The cell apoptosis rate was measured using an Annexin V/propidium iodide assay through flow cytometry. The expression levels of p53, Bax, Caspase3, CYP1, CYP2, and Bcl2 genes were evaluated using polymerase chain reaction, and Western blotting was performed for CYP1 to confirm the results. Our findings showed that C3G has dose-dependent cytotoxic effects on the MCF-7 cell line. According to flow cytometry results, the apoptosis of the cells 24 h after exposure to C3G was more than 51.5%. Moreover, after 24 h of exposure to the half-maximal inhibitory concentration of C3G, the expression of p53, Bax, Caspase3, CYP1, and CYP2 genes increased, and the expression of Bcl2 gene decreased. The Western blotting showed that CYP1 protein increased 2-fold compared to the control sample. The results of this study demonstrated that C3G has apoptotic and cytotoxic effects on breast cancer cells. Therefore, it is likely that this substance could be a suitable option for cancer therapy.