Snake diversity of the Aralo-Caspian basin includes 61 species in 8 families and is composed by local faunas of the Northern Caspian depression, Greater Caucasus and Ciscaucasia, Lesser Caucasus and Transcaucasia, Alborz and Turkmeno-Khorasanian mountains, Aralo-Caspian isthmus, deserts and mountains of the Middle Asia and plains of the Aral Sea region. Regions with richest snake diversity are Alborz, Turkmeno-Khorasanian mountains and Transcaucasia.