The article presents the original findings of Paracoenogonimus ovatus (Katsurada,1914) in fish in the Southern Bug and the Inhul rivers in Mykolaiv Region in 2012-2014. The roach (Rutilus rutilus), silver bream (Blicca bjoerkna), bream (Abramis brama), crucian (Carassius gibelio), rudd (Scardinius erythrophthalmus), pike (Esox lucius), pikeperch (Sander lucioperca) were found to be infected with metacercariae of P. ovatus. Metacercariae of P. ovatus are described based on the original material. The highest prevalence of infection was observed in the roach, 82.3 %, the pike was infected in the less degree, with prevalence of 15.3 %. The infection intensity was highest in the roach, up to 247 specimens; that of the pikeperch was the lowest - 17 specimens. The highest occurrence of P. ovatus was observed in the parts of the river Southern Bug in Zhovtnevy, Mykolaiv, Novoodesky Districts, whereas in Voznesenky, Pervomaysky Discticts and in the city of Mykolaiv the occurrence was the lowest. In the area of the river Inhul the parasite was observed mostly in the waters of Bashtansky District in Mykolaiv Region.