In several water bodies of the Dnipro river Basin, parasitological studies of the representatives of main taxonomic groups of freshwater zooplankton (Rotifera, Copepoda and Cladocera) were conducted. Altogether 22 species of diff erent taxonomic groups (bacteria, flagellates, algae, fungi, ciliates, etc.) of symbionts of zooplankters were found. The dataon the symbiofauna of zooplankters and on the aspects of biology of certain epibiotic and parasitic species were summarized. The study showed the peculiarities of symbionts distribution by host species in different taxonomic groups of zooplankton. The number of symbiotic species increased in following order: Rotifera > Cladocera > Copepoda. Copepoda had high species richness of epibiotic ciliates and the highest rates of colonization by epibiotic algae.