WRR-483, an analogue of K-11777, is a potent and selective cysteine protease inhibitor with trypanocidal activity in cell culture and animal model with comparable efficacy to K11777. WRR-483 demonstrates good potency against cruzain with sensitivity to pH conditions and high efficacy in the cell culture assay. Furthermore, WRR-483 also eradicates parasite infection in a mouse model of acute Chagas' disease. WRR-483 binds covalently to the active site cysteine of the protease in a similar manner as other vinyl sulfone-based inhibitors. WRR-483 has potential to be developed as a treatment for Chagas' disease.