Examination on some factors of the season, age, veterinary hygiene conditions, breeding methods, terrain... influenced to the rate and intensity of Leucocytozoon infection in chickens, the results showed that: The chickens were infected Leucocytozoon with high rate and heavy intensity in the mountainous region. That was higher on the spring and summer in comparation with the autumn and winter. The infected intensity and rate of Leucocytozoon increased gradually in correlation with chicken's age. The propotion of Leucocytozoon infection in good hygiene veterinary conditions was lower than that in bad hygiene conditions. The chickens in traditional breeding method were infected Leucocytozoon with high rate and heavy intensity in comparation with industry breeding method.