(Uploaded by Plazi for the Bat Literature Project) Results of recent molecular studies cast doubt on the validity of the superorder Archonta, suborders Megachiroptera and Microchiroptera, and infraorder Yinochiroptera and has even led some to consider novel alternatives for the evolution of flight and echolocation in mammals. At present, higher-level relationships within Chiroptera still is without consensus, and much of this controversy is related to how bats are related to other mammals and also to relationships among family-level lineages within Chiroptera. Although this controversy superficially manifests itself as differences in the relative merits of morphologic versus molecular data, both classes of data are themselves conflicting. We contend that much of the discrepancy among these studies is due to improper choice of out-group, limited taxonomic sampling, or both. We examined approximately 3 kb of mitochondrial DNA from 104 bats representing the taxonomic, geographic, and morphologic diversity within all families (except the monotypic Craseonycteridae) and 58 additional taxa representing 12 other orders of mammals. Results of our analyses strongly support other recent work indicating that Archonta is not a natural assemblage and that the sister taxon to Chiroptera may include Cetartiodactyla, Perissodactyla, Carnivora, and possibly Pholidota. Using representatives of these taxa as out-groups to evaluate interfamilial relationships within Chiroptera, we detected strong support for recognition of the suborders Yinpterochiroptera and Yangochiroptera. Within Yangochiroptera, our analyses strongly support expansion of the superfamily Noctilionoidea to include the New World Thyropteridae and Furipteridae.