(-)-Epigallocatechin-3-gallate (EGCG) is the major tea catechin and accounts for 50-80% of the total catechin in green tea. (-)-Epigallocatechin-3-gallate has antioxidant, anti-inflammatory, anti-microbial, anti-cancer, and anti-trypanocidal activities. This report describes the inhibitory effect of (-)-Epigallocatechin-3-gallate on the in vitro growth of bovine Babesia parasites and the in vivo growth of the mouse-adapted rodent babesia B. microti. The in vitro growth of the Babesia species was significantly (P<0.05) inhibited in the presence of micromolar concentrations of EGCG (IC50 values=18 and 25 microM for B. bovis, and B. bigemina, respectively). The parasites showed no re-growth at 25 microM for B. bovis and B. bigemina in the subsequent viability test. The drug significantly (P<0.05) inhibited the growth of B. microti at doses of 5 and 10 mg/kg body weight, and the parasites completely cleared on day 14 and 16 post-inoculation in the 5 and 10 mg/kg treated groups, respectively. These findings highlight the potentiality of (-)-Epigallocatechin-3-gallate as a chemotherapeutic drug for the treatment of babesiosis.