Resumo. In this study, Isosomodes kopenawai Perioto & Lara, sp. nov. (Hymenoptera, Eurytomidae) is described and illustrated, based on a female specimen collected near Manaus, Amazonas, Brazil. The new species is distinguished by a combination of morphological characters, including head coloration (brown to orange), mesosomal orange pigmentation, and propodeal structure (foveate with a deep, narrow, laterally carinate median channel). An updated identification key to Isosomodes species is provided.