The emerald ash borer Agrilus planipennis, which is native to East Asia, is a highly destructive pest of ash trees (Fraxinus sp.) in European Russia and North America. This quarantine species is currently spreading in the European part of Russia and in the east of Ukraine. The purpose of this study is to determine the distribution of the species in the southeast of the main part of the invasive range. The material was collected in Tambov, Voronezh, and Volgograd oblasts of the European part of Russia in 2021. The pest has spread to the central part of Tambov oblast, has almost completely populated Voronezh oblast, and has penetrated into the northwestern part of Volgograd oblast. Findings of Agrilus planipennis have shown that the invader continues to spread to the southeast of the European part of Russia. The border of the invasive range of Agrilus planipennis is already located in the immediate vicinity of the regions of the European part of Russia where the common ash is one of the main forest resources. Further expansion of the pest will cause significant ecological and economic damage.