The palaeontological material from the Dacian Basin provides a complete and well-represented record of faunal succession during the important faunal turnover called the Pachycrocuta event. The present study describes fossil remains of ruminants (Cervidae, Bovidae, Giraffidae) from the Early Pleistocene of Valea Grăunceanului, Fântâna lui Mitilan and other smaller sites from the Olteț River Valley. The article discuss the taxonomic context, eco-morphology and functional morphology of the described taxa and dynamics of biogeographic distribution. The commutity of ruminant species from the Dacian Basin before the Pachycrocuta event is dominated by Pliocene holdovers: Pliotragus ardeus, Gazellospira torticornis, Rucervus radulescui, Metacervocerus rhenanus and Mitilanotherium inexspectatum. This assemblage also contains new forms for Western Eurasia as Dama eurygonos, Eucladoceros dicranios, Eucladoceros ctenoides, Alces sp. and Bison (Eobison) sp. This specific regional fauna of ruminants became extinct during the Pachycrocuta faunal turnover and was replaced by a more cold-adapted assemblage of ruminants (Megalovis latifrons, Eucladoceros sp., Dama sp., Praemegaceros obscurus and its specialised diminished form Praemegaceros cf. mosbachensis) that show a greater affinity with coeval Levant faunas. The revealed dynamics of paleobiogeographic zones from the Early Pleistocene of southeastern Europe supports the hypothesis of early hominin dispersals in Western Eurasia via Balkan-Anatolia path.