In this study we assert that most of the "Pontian" stratigraphic succession of western Hungary is much older than Pontian stage (older than 7 Ma). In fact, these strata form a clearly distinct chronostratigraphic unit between the Pontian strata (as they are defined in the type area of the Black Sea basin) and the Pannonian strata (as they are de- fined in the type area of the Vienna basin). To denote such a problematic chronostratigraphic interval we propose the in- troduction of a new stage (or substage) named Transdanubian between the Pannonian sensu stricto (s.s.) and Pontian s.s. stages of the Upper Miocene series of the Central Paratethys System (ca. 9.0-7.4 Ma in the chronology adopted in this study). The Transdanubian stage has been defined in terms of biostratigraphy, lithostratigraphy, magnetostratigraphy and allostratigraphy. The location of a suitable stratotype has also been proposed. As a first approach, we tried to avoid the in- troduction of new terms in the already complex chronostrati- graphic nomenclature of the Pannonian basin. However, we arrived to the conclusion that the introduction of the Trans- danubian as a new stage (or substage) is a necessary break- through, to avoid further confusion and circular reasoning in- volving facies associations versus chronostratigraphic units. Transdanubian strata represent a distinct anticipation of the Pontian facies within the intra-Carpathian area. The fact that these strata have been reported for decades as "Pontian" in the literature has been the source of much terminological confusion and chronostratigraphic miscorrelation.