We inferred the phylogenetic relationships among 58 genera of Sericostom-atoidea, representing all previously accepted families as well as genera that were notplaced in established families. The analyses were based on ve fragments of the proteincoding genes carbamoylphosphate synthetase (CPSase of CAD), isocitrate dehydroge-nase (IDH), Elongation factor 1a (EF-1a), RNA polymerase II (POL II) and cytochromeoxidase I (COI). The data set was analysed using Bayesian methods with a mixedmodel, , and parsimony. The various methods generated slightly different resultsregarding relationships among families, but the shared results comprise support for: (i)a monophyletic Sericostomatoidea; (ii) a paraphyletic Parasericostoma due to inclusionof Myotrichia murina, leading to synonymization of Myotrichia with Parasericostoma;(iii) a polyphyletic Sericostomatidae, which is divided into two families, Sericostom-atidae sensu stricto and Parasericostomatidae fam.n.; (iv) a polyphyletic Helicophidaewhich is divided into Helicophidae sensu stricto and Heloccabucidae fam.n.; ( v) hypoth-esized phylogenetic placement of the former incerta sedis genera Ngoya, Seselpsycheand Karomana; (vi) a paraphyletic Costora (Conoesucidae) that should be divided intoseveral genera after more careful examination of morphological data; (vii) reinstatementof Gyrocarisa as a valid genus within Petrothrincidae. A third family, Ceylanopsychi-dae fam.n., is established based on morphological characters alone. A hypothesis ofthe relationship among 14 of the 15 families in the superfamily is presented. A key tothe families is presented based on adults (males). Taxonomic history, diagnosis, habitatpreference and distribution data for all sericostomatoid families are presented.