Turkey poults were experimentally infected with various doses of oocysts of the E. adenoeides and E. meleagrimitis species. The results of the clinical development of the disease, mortality rate, and changes in the feces were followed up. It was established that clinically the disease was manifested between the third and fourth day with E. adenoeides, and between the fourth and fifth day with E. meleagrimitis with dullness, bristling of feathers, head dropping, going off feed or full loss of appetite, thirst, and aggregation into groups. The feces were changed--either softened or fully watery, with bloody filaments (E. adenoeides). Mortality rate ranged from 0 to 100 per cent, depending on the species and the infective amount. The shedding of oocysts was followed up from the fifth up to the fifteenth day. It proved highest from the 5th to 7th day following infection. It was also found that the changes in the body weight showed as essential difference between infected and control birds. It was as early as the seventh day that there set in a rise of the live weight with all infected birds, which was negligible with those treated with high amounts--80 000 oocysts of the E. adenoeides sp.