Weed flora in Serbia is characterized by high diversity, comprising a total of 741 species classified into 322 genera and 63 families. Many weed species are not strictly specialized and occur in two or more weed categories. Out of the total number of species, class Liliopsida (Monocotyledones) includes 85 species (11.48%) and the class Magnoliopsida (Dicotyledones) 655 species (88.51%). The Equisetopsida is represented by 3 species. The most common families include 618 species altogether. According to the number of species, the most important are: Asteraceae (112), Poaceae (78), Fabaceae (52), Lamiaceae (47), Scrophulariaceae (46), Brassicaceae (44), Caryophyllaceae (40), Apiaceae (28), Chenopodiaceae (25), Ranunculaceae (23), Rosaceae (22), Boraginaceae (18), Cyperaceae (11), etc. The following genera are prominent by their number of species: Veronica (19), Chenopodium (16), Ranunculus (12), Rumex (13), Vicia (12), Bromus (11), Euphorbia (11), Centaurea (9), Galium (7), Trifolium (6), etc.