The present study was carried out to provide insight on the floristic composition, vegetation analysis and species diversity of associated flora of three common Brassica spp (Brassica rapa L., Brassica nigra (L.) Koch and Brassica tournefortii Gouan) communities in the North of Nile Delta of Egypt. In 60 surveyed stands, a total of 150 species belonging to 122 genera and related to 34 taxonomic families were recorded. Annual/therophytes-biregional taxa were the predomninates. Vegetation classification distinguished four vegetation groups named after the first and second dominant species. Group A: Cichorium endivia-Brassica nigra and represents the vegetation type of old field crops cultivated with clover and wheat, while group B: Polypogon monspeliensis- Rumex dentatus and represents winter field crops in old cultivated lands, edges of cultivation (canal banks) and roadsides. Group C: Brassica tournefortii- Cynodon dactylon and was characteristic for newly reclaimed lands, while group D: Echinops spinosus-Brassica tournefortii was found in the roadsides and sand formations habitat along the Deltaic Mediterranean coast of Egypt. The highest species diversity was mainly in groups D and C from roadsides and sand formations habitat and in the newly reclaimed lands. Edaphic factors especially sulphates, bicarbonates, maximum water-holding capacity, total phosphorus, silt, magnesium, potassium, potassium adsorption ratio, sand fraction and chlorides affect the distribution and abundance of the characteristic weeds species.