The paper presents the results of studying the adventive component of the seed bank of the Oak Mane Island of the Volga River Valley in the vicinity of the city of Saratov. Seeds of 12 species of adventitious plants were registered in the seed bank of the studied forest communities. All identifi ed seeds belong to plant species belonging to one department of Magnoliophyta, 8 families and 12 genera. The Asteraceae family plays a leading role in the taxonomic spectrum of adventitious seed bank species (42%). Mesophytic mesotrophic (63.6%) heliophytic grouping of plants dominates in relation to ecological regimes. Mostly there are species of North American origin (60%). Herbaceous annuals (33% of species) and trees (34%) play a signifi cant role. A signifi cant impact on the composition of seed banks was caused by the unintentional entry of seeds of plants that are “refugees from culture” into this territory. Most adventitious plants, represented by both vegetating individuals and seeds, have penetrated into natural cenoses, and in some cases even partially transformed their structure, which is due to their reproductive potential and ability to compete with representatives of the native fl ora of natural habitats. In the studied area, foci of the concentration of seeds of drift plants in diff erent communities were revealed, in continuous placement (Acer negundo, Bidens frondosa and Populus alba), disjunctive (Fraxinus pennsylvanica, Parthenocissus quinquefolia, Echinocystis lobáta, Impatiens glandulifera), sporadic – Ambrosia trifida, Artemisia sieversiana, Crataegus sanguinea, Inula caspica and Ulmus pumila. An increase in the number of adventitious species presented in the seed bank was recorded, but the number of seeds decreased.