Karyotypes of representatives of four genera of the subfamily Stenoderminae (Phyllostomatidae), Ardops, Ariteus, Phyllops, and Ectophylla are presented. Karyotypic characteristics of Ardops, Ariteus, and Phyllops support a close relationship between these genera and the genera Stenoderma and Ametrida. The karyotype of Ectophylla alba does not support the conclusion that it is congeneric with the morphologically similar Mesophylla. Chromosomally, Mesophylla and Vampyressa pusilla are more closely related to each other than either is to Ectophylla or the other species of Vampyressa that have been karyotyped. Evolutionary, early distributional, and taxonomic aspects of the genera involved are discussed.