Bidens pilosa L. (Asteraceae) is an annual or perennial cosmopolitan noxious herb. Populations of this species showed conspicuous pheno-plasticity in Egypt; with taxonomic argument not yet resolved. This study was aimed to identify the taxonomic identity of this species to infra-specific level and deduce the features distinguishing each taxon. Morphological differentiation between the three varieties depend on their ray florets; Ray florets in var. radiate are longer than 10mm, in var. minor are less than 8mm while they are totally absent in var. pilosa. The identified taxa documented using plastidial rbcL region barcoding. The taxonomic revision based on morphologic traits proved that B. pilosa L. is represented in Egyptian flora by three varieties (var. radiata, var. minor and var. pilosa). var. minor and var. pilosa are new records to the Egyptian flora. The three identified varieties were documented by DNA-barcoding using the plastidial rbcL region and deposited in GenBank for the first time with the accession numbers OR544109; OR544110 and OR544111.