The current study was conducted to detect the presence of Buxtonella sulcata (an intestinal ciliate) in faecal samples of cattle suffering from diarrhea in Mosul city. One hundred and twenty faecal samples were examined, and collected from calves (44), beef cattle (34) and dairy cattle (42) these animals were divided into two groups those showed diarrhea (86) and (34) had no symptomatic diarrhea. Direct smear and formalin-ether sedimentation methods were used for detection of this parasite. The total percentage of infection with Buxtonella sulcata was 24.16%. There was no significant differences in the percentage of infection and intensity of infection between calves, beef and dairy cattle where as there were significant differences between diarrheic and non-diarrheic animals.