All U.S. tarantulas belong to the genus Aphonopelma, a patchwork genus with 54 species currently described. However, the species-level taxonomy of Aphonopelma is deficient in several respects. Even though members of this genus are relatively homogeneous morphologically, the majority of species were described from only 1 or 2 specimens. This research focuses on the Aphonopelma hentzi complex, a group of about 10 morphologically similar species native to the south-central U.S. Our investigation employs an integrated set of molecular and morphological characters to test the hypothesis that all specimens in the hentzi complex represent a single wide-ranging species. We have completed a species-level phylogenetic analysis, based upon partial sequences of the 16S rRNA and COI genes in addition to various morphological characters.