The phenomenon of coevolution in seven genera of lizards from the subfamily Iguaninae, and 22 species of their nematode parasites, was examined using cluster analysis of the lizard helminthofauna similarity. The resulting dendrogram topology correlated approximately with the evolutionary and taxonomic division of the tribe Iguanini into two monophyletic groups: Amblyrhynchina Queiroz, 1987, and Iguanina Bell, 1825. Moreover, the results suggest that within the Iguanina group, the relation between the genera Iguana and Ctenosaura can be considered closer and narrower than it was presumed.