Through examination of one hundred fecal samples collected from buffaloes in different regions of Mosul  city. The total percentage of infection with Buxtonella sulcata was (35%). No significant differences were recorded between different sexes and ages of animals. Cysts of Buxtonella sulcata were diagnosed in animals with or without diarrhea but large number of cysts appeared in feces of animals suffering from diarrhea (48.57%). Histological examination of large intestine revealed the presence of the Buxtonella sulcata associated with necrosis, hyperplasia of the intestinal epithelium, different degrees of hemorrhages, and infiltration of inflammatory cells.