A chromosome analysis on nineVernoniaspecies (Vernonieae, Asteraceae) from South America was carried out. First chromosome counts are notified in four species:V. lilacinaMart. (2n=32= 24m + 6sm + 2st),V. oxyodontaMalme (2w=128),pulverulentaBaker (2n=96) andV. tarijensis(Griseb.) Hieron. (2n=32= 24m + 8sm). Furthermore, the somatic chromosome numbers ofV. chalybaeaMart, ex DC. (2n=32= 22m + l0sm),V.polyphyllaSch.Bip. (2n=64=: 40m + 20sm + 4st),V. squarrosaLess. (2n=64) andV. teyucuarensisCabrera (2n=160) are also confirmed. For V. aurea Mart, ex DC. is presented an unreported chromosome number (2n=32= 24m + 8sm). The karyotype analysis made on five species mainly showed metacentric and submetacentric chromosomes, differing in proportion between the species. InV. lilacinaandV. polyphyllawere also found one and two subtelocentric pairs respectively. The nine analyzed species presented x=16, a basic chromo some number very frequent in South America, specially in species from the subsect. Macrocephalae Baker. The chromosome number 2n=32 found inV. aurea, V. chalybaea, V. liladnaandV.tarijensissuggests that these species, included actually in other group, should be transferred to the subsection Macrocephalae