The analysis of the results of studies of the distribution of pathogens of cryptocotylosis in the body of gobies is given (Mesogobius batrachocephalus Pallas, 1814, Neogobius melanostomum Pallas, 1814, Neogobius fluviatialis Pallas, 1814). Modern informational data from the scientific literature on the spread of this parasite in Ukraine and the world are presented. It has been established that the main place of localization of pathogens of cryptocotylosis is the dorso-cranial part of the body. The highest infection rates were recorded in the area of the first and second dorsal fin – 20.8 and 19.9%, respectively. On the surface of the head, 19.4% of the total number of detected parasites was recorded. The caudal fin section was also marked by rather high rates of invasion – 15.1%. Gills, from dorsally located sites, had the lowest infection rate – 11.2%. The presence of pigmented cysts on the surface of gill lobes was noted on the gills. At high rates of invasion intensity, the gills were covered with a small amount of viscous opaque mucus. Structural changes were noted in the gill lobes, namely, it was recorded that some areas are somewhat more anemic than others. In the pectoral fin region, 10.7% of all identified parasites of the studied species were recorded. The region of the anal fin was the lowest indices – 2.6%. According to the results of studies, it was found that the causative agent of cryptocotylosis can also be localized in places uncharacteristic of its life cycle – the inner wall of the abdominal wall. It was revealed that on the inner side of the abdominal wall was only 0.3% cryptocotylus. During the study of the tissues of the abdominal wall, signs that cercaria had penetrated externally were not established. Obviously, the appearance of metacercaria on the inner side of the abdominal wall is explained by the ingestion of cryptocotylus by сercaria, at the stage of migration, and the passage of the latter through the wall of the intestinal tube. It was noted that metacercariae of varying degrees of oblivion were recorded on the gills. Larvae of trematodes that have recently invaded bull-calves were less pigmented than those that parasitized fish for a certain time. Inflammation on the surface of the gills was noted.