The adult stage of the plume moth Adaina jobimi sp. nov. (Lepidoptera: Pterophoridae: Pterophorinae: Oidaematophorini) from the arid highlands of the western slopes of the Andes of northern Chile is described and illustrated. The wing pattern and genitalia of A. jobimi resemble those of A. excreta Meyrick, 1930, from Argentina, Ecuador and Peru and A. coquimboae Gielis, 2012, the only representative of the genus previously known from Chile. Morphological differences of A. jobimi with these two congenerics are discussed. Larval feeding and pupation of A. jobimi occur on inflorescences of the native shrub Baccharis alnifolia Meyen & Walp. (Asteraceae). The discovery of A. jobimi provides the first record of the genus in a long distribution gap in mainland South America west of the Andes Range, suggesting that the taxonomic diversity of Adaina in this area deserves further attention.