A review of the aquatic and semi-aquatic beetles collected from the 'Sarykumskie Barkhany' section of the Dagestan Nature Reserve is provided. Altogether, 61 water-associated and terrestrial (Helophorus nubilus Fabricius, 1777 and three species of Cercyon Leach, 1817) beetle species are recorded from this territory, of which 44 species are recorded for the first time from the studied area, 18 species are newly reported from the Dagestan Republic, and eight species are newly recorded from the North Caucasus Region. Ochthebius lividipennis Peyron, 1858 (Hydraenidae) is reported for the first time from Russia. Also, because of possible discovery of Dryops caspius (Ménétries, 1832) (Dryopidae) in the territory considered, the lectotype of this species is designated in the current work. [ABSTRACT FROM AUTHOR]