The authors have identified the species complex of weeds, for which the conditions of heat and moisture supply in Voronezh Oblast are suitable. For this purpose ecological and geographical analysis was used. Its first stage consisted in identifying the values of heat and moisture factors that limit the propagation of plant species in even lands in the northern direction (the isoline value of the average annual sum of active temperatures above +5°C that describes the northern boundary of species distribution zone in the Russian Federation) and southern direction (the average annual value of hydrothermal coefficient isoline, which describes the southern boundary of the zone of major distribution of species in the Russian Federation). The second stage included comparing the obtained values with similar values of isolines describing the Northern and the Southern boundaries of Voronezh Oblast. A complex of 135 species of weed plants commonly growing in the specified territory has been identified and verified by th