The prevalence of the helminth infections of the Nile fishes Bagrus bayad, Clarias lazera, Tilapia nilotica and Barbas bynni was investigated. 234 (66.5%) out of 352 examined freshwater fishes were infected with the helminth parasites. Single or mixed infections were noticed among the infected fishes. Out of the the fish examined, 72.2% were found harbouring Trematode parasites, 8.1% harboured nematodes and 35.9% haboured acanthocephalans.The prevalenc of helminth parasites is widely varied according to the size and sex of the hosts. The overall prevalence of infection wi th the helminth parasi tes in B. bayad, C. Lazera and T. nilotica was slightly higher in female fishes than male ones. Among B. bynni, the prevalence of infection was nearly the same in both sexes. Long size fishes of C. lazera and B. bynni were more infected in both sexes, while higher prevalence occurred in intermediate size groups in both sexes of B. bayad and T. nilotica. The relationship between the prevalence of infection of each species of the helminth parasi te and the size and sex of the four Nile fishes were discussed.