In a study conducted to investigate the incidence of the protozoan parasite Cryptosporidium in Nile fishes 100 specimens were studied. The intestinal contents of fishes belonging to Tilapia nilotica, Clarias lazera, Synodontis schall, Bagrus bayad and Schilbe mystus were survey ed for parasitological examination. The recovery rate was 12% accord ing to species of which Tilapia nilotica (30%), Clarias lazera (20%), and Bagrus bayad (10%) proved to be natural hosts of Cryptosporid ium. The pathogenicity of the parasite which is now regarded as a newly-emergent zoonosis was discussed.