Abstract A phylogenetic analysis for the Cimicomorpha was conducted using 92 taxa, including eight outgroups and six species of Thaumastocoridae. Density of taxon sampling allows for tests of relationships at the family level for most taxa, whereas in the Miridae denser sampling allows for doing so on the tribal level. This level of sampling also corresponds with the availability of testable published hypotheses of relationships. Morphological data for 73 characters are coded for all taxa. Approximately 3500 base pairs of DNA were sequenced for the following gene regions for 83 taxa: 16S rDNA, 18S rDNA, 28S rDNA and COI. Results are presented for analysis of morphological data, individual molecular partitions, combined molecular data, combined morphological and molecular data for 83 taxa and combined morphological and molecular data for 92 taxa. Analyses of morphological data were performed using the parsimony programs nona and piwe: molecular and combined data were analysed using direct optimization with the program poy. Major conclusions of the present study include recognition of the following monophyletic groups: The Geocorisae is a monophyletic group. The monophyly of the Cimicomorpha – including Thaumastocoridae – is not supported in most analyses. The Reduviidae is monophyletic, with the Phymatinae Complex being the sister-group of the remaining subfamilies. The circumscription of the Cimiciformes is altered from the prior conception of Schuh and Štys to also include the Joppeicidae, Microphysidae and Velocipedidae, as well as the recently described family Curaliidae; the monophyly of the Cimiciformes is supported in most analyses; the Cimiciformes is treated as the sister-group of the Miroidea in most analyses. The monophyly of the Cimicoidea, including Curaliidae, is supported in all analyses including molecular data, whereas Curaliidae is treated as a more basal cimiciform in all other analyses. The monophyly and placement of the Thaumastocoridae is ambiguous across the range of analyses, and the monophyly of the Miroidea sensu Schuh and Štys receives limited support in the combined analyses of morphology + molecular data. The Tingidae and Miridae are each monophyletic and together almost invariably form a monophyletic group. Within the Miridae, several inclusive monophyletic groups at the subfamily/tribal level are more or less consistently recognized when molecular data are included; however, the interrelationships of the subfamilies vary substantially across the range of analyses. Of the individual molecular partitions, only 18S rDNA shows significant congruence with combined analyses of morphological, combined molecular or combined morphological and molecular data. Scenarios are discussed for the evolution of the metathoracic scent-efferent system and the origin of the fossula spongiosa.