Although some studies have evaluated the cytotoxic activity of different Fabaceae species, there has been only limited research into the cytotoxic effect of Dorycnium pentaphyllum. The purpose of this study was to determine the antioxidant properties and cytotoxic effect of D. pentaphyllum extract on various human cancer cells. The total phenolic content (TPC) of the extract was determined using colorimetric method. The cytotoxic effect of the extract on human lung (A549), liver (HepG2), and breast (MCF-7) cancer cells and a normal human fibroblast cells was assessed using the MTT assay. TPC value of extract was found as 140.3 +/- 1.1 mg gallic acid equivalent per g sample. Extract showed selective cytotoxicity on all studied cancer cells compared to normal fibroblast cells, and the IC50 values of the extract in the cancer cells range from 100.4 to 298.5 mu g/mL. This is the first study to reveal the cytotoxic effect of D. pentaphyllum extract on cancer cell lines. Phytomedical applications of D. pentaphyllum may represent promising approaches in the treatment of cancer.