The monophyly of the 7 infraorders of Heteroptera and history of higher group concepts and interrelationships within the Heteroptera are briefly reviewed. Data from 31 morphological characters are combined with 669 bases of 18S nuclear rDNA for 29 taxa, including several outgroups to the Heteroptera, to produce a phylogeny based on the total available evidence. The molecular data alone and in conjunction with morphological data indicate that: the Homoptera are probably not monophyletic; the Auchenorrhyncha are the sister group of Coleorrhyncha + Heteroptera ; the Enicocephalomorpha are the sister group of remaining Heteroptera; the Dipsocoromorpha are the sister group of remaining Heteroptera; the Gerromorpha are the sister group of remaining Heteroptera; the Nepomorpha are the sister group of remaining Heteroptera; the Leptopodomorpha are the sister group of the Cimicomorpha + Pentatomomorpha. The molecular evidence corroborates the morphologically based theory of a sister group relationship between Aradoidea and trichophoran Pentatomomorpha. This scheme deviates from that previously published by Schuh, in which the Leptopodomorpha were treated as the sister group of the Nepomorpha.