The cystozoites of Sarcocystis muris were infective to other mice after peroral inoculation. They transformed into gamonts and after fertilization underwent sporulation with the production of infectious oocysts/sporocysts in the lamina propria of the small intestine. The present study demonstrated that S. muris possesses both diheteroxenous and dihomoxenous life cycle and can be transmitted by the cannibalism among mice.