Trypanosoma rangeli, the only trypanosome besides Trypanosoma cruzi to infect humans in the Americas, shows an important geographical overlap with the agent of Chagas disease, and its taxonomic position has been the source of some controversy. This study utilizes beta-tubulin gene sequences for investigating the phylogeny of this species. All trees, produced with the different algorithms utilized, always grouped T. rangeli with Trypanosoma brucei in preference to T. cruzi. In addition evidence suggesting that the genus Trypanosoma may be polyphyletic was found.