Geographic distribution of some 350 taxa from the Caspian and Black Sea basins were analyzed with regard to recent taxonomy, phylogeny, endemicity and ecological classification. A check-list of the Caspian Sea fishes (taxa from families down to subspecies) is provided. Eighty species and subspecies permanently occur or occasionally recorded from the North Caspian while 33–35 species and subspecies being only distributed in the Middle and South Caspian. Forty-four species are common for the two ecoregions. A comparison of the Caspian and the Black Sea fish faunas and their historical evolution is given with special respect to palaeogeography and palaeohydrology of the basin.