Worldwide, and in Jordan specifically, date palm fruit production has been steadily increasing. Recently, various dates extracts have been used functionally as antioxidants or anticancer agents. In addition, Jordanian date palm fruit of Barhi variety at two maturity stages (Rutab) and (Tamr) inhibited chemically-induced mammary cancer in animal model. The aim of this study is to strengthen the scientific evidence on the effect of dates on mammary cancer via assessing the effect of different concentrations of water extracts of three varieties of dates grown in Jordan (Barhi, Belle Huwaimil, and Medjool) at two maturity stages (Rutab and Tamr) on the viability of MCF-7 breast cancer cell line. The effects of different extracts on MCF7 inhibition/proliferation was analyzed using MTT assay. Percentage of inhibition was calculated. The most effective concentration was 100 mg/ml for all varieties. At this concentration, Medjool variety at the Tamr stage exhibited the highest inhibition. At the 12.5 and 25 mg/ml concentrations of the extracts, the most effective date palm fruit varieties were Belle Huwaimil and Barhi at the Tamr stage respectively. At lower concentrations (3.125 and 6.25 mg/ml), Medjool at the Tamr stage and Belle Huwaimil respectively were the most effective extracts were Barhi at the Tamr and Rutab stages were the least effective (P=0.000**). It is concluded that water extract of palm fruit reduced MCF-7 cell viability.