The authors propose a revision of the nomenclature of the formational units Auct., defining new lithostratigraphic, depositional and synthem units within the Tertiary sedimentary successions cropping out in Southern Sardinia, in particular those of Miocene age. Each lithostratigraphic unit has been placed within the latest zonal schemes of the Mediterranean planktic foraminiferal assemblages and calcareous plankton zonal maps. The bathymetric plane for each unit has been determined either on the basis of existing data or analysing new autoecological/paleoecological data collected by the authors on the autochthonous benthic species. In an attempt to revise the Tertiary stratigraphy in the south of the island, in accordance with the standards established by the Sub-commission on Neogene Stratigraphy, three second-order cycles (sensu Haq et alii, 1997) have been recognised in the Chattian-Messinian interval. Within these second-order cycles several third-order cycles and numerous depositional systems have been distinguished. Several unconformity-bounded stratigraphic units (UBSU) have also been identified. Finally, the major sedimentary, tectonic and volcanic events that occurred on the island between the Oligocene and the Pliocene are briefly outlined, also viewed in the broader context of the geodynamic evolution of the western Mediterranean.