Barbatodon transylvanicus is the first mammal described from the Mesozoic of Romania, based on an isolated molar found in the Maastrichtian continental deposits near Pui village. This tooth was subject of controversies since its discovery, being considered either a first upper or lower molar by different authors, even receiving different names. The systematic affinities and paleobiogeographic significance of this taxon were accordingly poorly understood. The peculiar morphology of the holotype was the main reason for the uncertainties concerning the specimen, hindering for long time the understanding of its true affinities and relationships. Barbatodon was listed until recently as probable member of the Paracimexomys group, a “Middle”-Late Cretaceous North American clade. The discovery of a partial multituberculate skeleton at Pui allows the critical reassessment of the validity and relationships of Barbatodon transylvanicus. The new specimen includes the almost complete lower dentition, associated with M2; comparisons with other Haţeg multituberculate remains suggest it is referable to Barbatodon transylvanicus. Barbatodon transylvanicus is shown to be a valid taxon, that belongs together with other multituberculates from the Haţeg Basin and the Cretaceous-Paleogene genus Hainina to the European endemic family Kogaionidae. This taxonomic reinterpretation has also important systematic and paleobiogeographic consequences.