Relationships within the primate order Omomyidae are assessed with dental and postcranial data, using cladistic techniques. Quantitative and qualitative characters of the dentition, mandible, maxilla and, where known, calcaneus and astragalus were evaluated for 28 omomyid species. Characters were subjected to a series of parsimony analyses including dental only, and combined dental and postcranial data, as well as evaluations with limited and expanded numbers of taxa. Trees were rooted through the use of a hypothetical outgroup taxon consisting of closely related primate and nonprimate taxa. Tarsal elements showed variability within the Omomyidae and this variability contained phylogenetic signal. When all dental and postcranial data were evaluated cladistically, omomyids prove to consist of three subfamilies: Omomyinae, Anaptomorphinae, and Microchoerinae. The omomyines consist of the tribes Washakiini, Uintaniini, Omomyini and Macrotarsiini, whereas the anaptomorphines consist of a paraphyletic Trogolemurini and Anaptomorphini. The European subfamily Microchoerinae seems more closely related to Anaptomorphinae. Species traditionally allocated to the genus Teilhardina are paraphyletic and may warrant generic distinction. Taxonomic actions include the descriptions of Arapahoviina Tornow new subtribe and Bazius Tornow new genus, and transfer of Loveinia wapitiensis Gunnell, Bartels, Gingerich and Torres, 1992 to the new genus as Bazius wapitiensis new combination.