An annotated inventory of the 40 species and 12 genera of Chrysomelinae from the Mongolian Altai is presented. Four species of leaf beetles, Chrysolina quadrangulata Motschulsky, 1860, Chrysolina graminis (Linnaeus, 1758), Phratora polaris (Schneider, 1886), and Phratora vulgatissima (Linnaeus, 1758), and one subspecies, Chrysolina perforata simillima Mohr, 1966, are newly recorded for the Mongolian Altai. Three species, Crosita clementzae Jacobson, 1899, Phaedon armoraciae (Linnaeus, 1758), and Entomoscelis adonidis (Pallas, 1771), and one subspecies, Gastrophysa viridula lenta (Weise, 1887), are new records for Bayan-Ulegei aimak. Two species, Chrysolina perforata (Gebler, 1830) and Phaedon concinnus Stephens, 1834, are new records for Gobi-Altai aimak.