The paper deals with the inventory of the fish species, their distribution and ichthyofauna in the Irpin River basin after the end of hostilities. During the period of investigations, 36 fish species were recorded. For the first time in the basin we recorded <i>Ballerus ballerus, Aspius aspius</i> and <i>Neogobius melanostomus</i>. In the fish fauna structure, the aboriginal species prevailed. Their contribution to the total numbers accounted for 56.5-98.7%. The complex of rare fishes comprised three species listed in the Red Data Book of Ukraine: <i>Alburnoides rossicus, Leuciscus leuciscus</i> and <i>Carassius carassius</i>, and also five species listed in the Resolution 6 of the Berne Convention: <i>Cobitis taenia, Rhodeus amarus, Misgurnus fossilis, Sabanejewia aurata and Aspius aspius</i>.
The ichthyofauna structure analysis revealed separate groups in the middle, the least transformed part of the basin, and in the lower section of the Irpin River, in the area flooded owing to the dam explosion, where the specific ichthyocenosis was formed comprising new species from the reservoir and elevated portion of the limnophilous fishes. Ichthyofauna in sites located in the territory most affected by hostilities, but outside the flood zone, on the whole corresponded to the general patterns of species distribution and structure typical to natural ichthyocenoses.