Diplostomoses is widely spread disease of freshwater fishes caused by meta-cercaria trematode of the genus of diplostomum (family diplostomide, orderly strigeidida). There were exposed 17 species of this orderly in the fauna of Russia, each of which is capable of causing original disease. The document consists of 6 Secs. Section 1 lays down general provisions. Section 2 regards epizootology. Section 3 regards clinical symptoms and patologo-anatomical changes. Section 4 regards diagnosis. Section