Breast cancer is the most common malignancy in women, both in the developed and developing countries. Anthocyanins are natural coloring of a multitude of foods, such as berries, grapes or cherries. Glycosides of the aglycons delphinidin represent the most abundant anthocyanins in fruits. Delphinidin has recently been reported to inhibit the growth of human tumor cell line. Also, delphinidin is a powerful antioxidant that reportedly exerts beneficial effects in patients with advanced cancer by reducing the level of reactive oxygen species and increasing glutathion peroxidase activity. This study investigates the effects of delphinidin on protein ErbB2, ErbB3 and Akt expressions associated with cell proliferation and Bcl-2, Bax protein associated with cell apoptosis in MDA-MB-231 human breast cancer cell line. MDA-MB-231 cells were cultured with various concentrations (0, 5, 10, and $20{mu}mol/L$) of delphinidin. Delphinidin inhibited breast cancer cell growth in a dose dependent manner (p < 0.05). ErbB2 and ErbB3 expressions were markdly lower $5{mu}mol/L$ delphinidin (p < 0.05). In addition, total Akt and phosphorylated Akt levels were decreased dose-dependently in cells treated with delphinidin (p < 0.05). Futher, Bcl-2 levels were dose-dependently decreased and Bax expression was significantly increased in cells treated with delphinidin (p < 0.05). In conclusion, I have shown that delphinidin inhibits cell growth, proliferation and induces apoptosis in MDA-MB-231 human breast cancer cell lines.