Phylogenetic analyses of supraspecific relationship Entomobryioidea (sensu Szeptycki, i. e., Entomobryidae, Paronellidae, Cyphoderidae and Microfalculidae) are few and most are small sections in works dedicated to relationships among all springtail families. All authors have assumed the monophyly of Entomobryidae s. str. and the phylogenies they present only illustrate the placement of Paronellidae and Cyphoderidae with respect to Entomobryidae. However, there is evidence suggesting that Paronellidae and Cyphoderidae are not sister clades, but derived from within Entomobryidae. For example, all cyphoderids and paronellids have the fourth abdominal segment elongated, and more than twice the size of the third; in addition cyphoderids and many scaled paronellids have accessory setae associated with abdominal bothriotricha. These two characters are shared with Entomobryinae and Seirinae but not with Orchesellinae. Mari Mutt (1988) questioned the monophyly of Paronellidae after noticing the striking similarity in chaetotaxy between Lepidonella (Paronellidae ) and Lepidocyrtus (Entomobryidae). In a review of Paronellidae based on chaetotaxic characters Mitra (1993) supports Mari Mutt's suggestion by pointing out that Bromacanthus and Lepidonella could be derived from a Lepidocyrtus-like ancestor. Thus, some of the most important questions about the classification of Entomobryoidea are:1) are Paronellidae and Cyphoderidae sister clades to or derived from within Entomobryidae; 2) are the subfamilies of Entomobryidae as defined by Szeptycki (1979) monophyletic?; and 3) how these subfamilies relate to each.other. To address these questions I present a phylogenetic analysis of 27 genera of Entomobryioidea based on complete 18S rDNA sequences and 50 morphological characters.