The purpose of the research was to study helminthofauna of fish Cypriniformes order in comparative aspect in artificial and natural water bodies and the clarification ways of formation of faunal assemblages and development of scientific bases of prevention of helminthiasis of fish. An extensive and systematic research of helminthofauna of fish water bodies of the order Cypriniformes of the northeast of Uzbekistan has realized and taxonomic and faunal analysis of detected parasites has also been carried out. Fauna of parasitic worms of Cypriniformes in ponds of diverse Syrdarya river shows 49 species, 18 species belongs to the class Trematoda, Cestoda class represents 13 species, class Acanthocephala 4 species and the class Nematoda 14 species. Analysis of biological properties and ecological specialty of Cypriniformes parasitic worms allows three types of helminth communities: 25 species parasitizing Cypriniformes as definitive hosts; 19 species parasitizing as intermediate hosts and 6 species parasitizing as a reservoir (paratenetic) hosts. Dioctophyme renale was registered first time in roach for the water bodies of the Syrdarya river. Ordinary carp, in our research, according to as host a new host Nematode of the Raphidascaris acus larvae. On the basis of factual data the environmental factors of the quantitative and qualitative composition of cyprinids helminthofauna in the northeast of Uzbekistan is reported.