Ambrosia artemisiifolia L. (common ragweed) is an invasive alien plant (IAP) in the European part of the Russian Federation and in the Ukraine. Ragweed was introduced into the territory of Western Europe between 1860 and 1870 together with red clover seeds delivered from America, and has since spread and become a nuisance weed in agricultural land and disturbed habitats. This study presents a detailed overview of the history of introduction and distribution of this IAP in the territory of Russia and neighbouring countries. A map has been created to show species distribution dynamics in the European part of Russia and neighbouring countries from initial foci of introduction to date. A detailed map of current distribution in Russia and the Ukraine has also been created. The rate of expansion during the different time periods was calculated and compared with recent species distribution modelling allowing future spatial spread of ragweed to be forecast. In the European part of Russia, and in the Ukraine, the species has almost reached the edge of its environmental limitations and further expansion to the northern regions is expected to slow down.