Verticillium leaf mottle and wilt caused by the fungus Verticillium dahliae is a major disease of sunflower in Argentina and the USA. In the summer of 2013 an important outbreak of the disease occurred in one field in the Southwest of Spain. The determination of vegetative compatibility groups (VCGs) of V. dahliae is used in the genetic characterization of the fungus. Molecular markers have also been developed and applied for the analysis of V. dahliae particularly for those isolates infecting artichoke cotton and olive tree. The objective of this work was to determine the genetic and molecular features of V. dahliae of sunflower. Three V. dahliae isolates one from Argentina collected in 2012 and two collected in Spain in 2013 were analysed. The VCGs were determined by complementation between nit mutants of the isolates from sunflower and the VCGs reference strains. Molecular characterization was conducted by polymerase chain reaction using primer pairs that are diagnostic of either V. dahliae species defoliating or non-defoliating pathotypes or VCGs. Complementation tests between nit mutants and reference strains clearly showed that the three isolates from sunflower belong to the VCG2B. The VCG2B has been identified in V. dahliae from crops as cotton artichoke eggplant pepper and tomato among others. When molecularly analysed the three V. dahliae isolates infecting sunflower had the same molecular pattern than the one found for non-defoliating isolates of V. dahliae pathogenic to artichoke or cotton. The results of this work show the closeness between non-defoliating isolates of V. dahliae infecting artichoke cotton and sunflower and suggest that any of these three species can serve as carrier and source of inoculum for Verticillium outbreaks in them.