Abstract
The current study revealed the presence of oocysts of Cryptosporidium in the fluid and tissue of gall bladder of sheep which is slaughtered in Mosul city by using different diagnostic techniques, including direct smear method, staining method by modified Zeil-Nelseen stain, scraping of mucosal layer of gall bladder and histological examination, the percentage of infection 20% and there were significant differences in the percentages of infection between gall bladder 20% and fecal samples 41%. The histological study showed that the oocyst of Cryptosporidium was attached on the surface of the epithelial cells of gall bladder. The high percentage of infection appeared in ewes was 30% and there was no significant differences in the infection of gall bladder between rams and ewes.