Cryptosporidium is a widespread pathogen that affects a wideranging of vertebrate hosts including humans, in which it is one of 
the main causes of diarrhea . Marine and fresh water fishes also 
harbor Cryptosporidium species. Relatively little is known about the 
epidemiology and taxonomy of Cryptosporidium in fish. In the 
current study three hundreds and ten fishes were collected from 
Mediteranean sea as a group one representing wild marine fish 
(n=130) and River Nile as a group two representing wild fresh 
water fish (n=180). Intestinal smears were stained by modified 
Ziehl–Neelsen stain then microscopically examined using objective 
lenses 10x, 40x and 100x. the infection rate was 25.48% ,
Cryptosporidium recorded higher prevalence in wild fresh water 
fish (30.5%) than wild marine water fish (18.46%), with significant 
difference (P=0.0159). In wild marine fish Cryptosporidium
infection was higher in Sea bass (Dicentrarchus labrax) (22.8%) 
than Sea bream ((Sparus aurata) (13.33%),which doesnot show 
any significance (P=0.1629) . On the other side for fresh water fish 
the infection was higher in Tilapia nilotica (38.8%) than Mugil 
cephalus (22.2%), with significant difference (P=0.0152) . The 
present study provide the first assessed data on the prevalence of 
Cryptosporidium spp in wild marine and fresh water fish in Egypt. 
with future prospective to detect genetic characterization and 
zoonotic relationship of different Cryptosporidium genotypes in 
different type of fish.