ABSTRACT: Biostratigraphically important dinoflagellate, acritarch, and pollen events calibrated by planktonic foraminifers and calcareous nannoplankton are here documented for the first time in the Rupelian sediments of the Mus Basin, Eastern Anatolia. The LAD of Ascostomocystis potane in coincidence with the FAD of Globorotalia opima opima in the “late” Rupelian, the FAD of Wetzeliella gochtii in the “middle” Rupelian, the LAD of Wetzeliella gochtii in the “latest” Rupelian, and the FADs of Compositae (tubuliflorae type), Monoporopollenites gramineoides and Umbelliferae at the base of Rupelian should be of particular importance for regional correlations. In addition to the Rupelian acritarch Ascostomocystis potane, diverse dinoflagellate cysts such as Achillodinium biformoides, Wetzeliella gochtii, Membranophoridium aspinatum, Distatodinium biffii, Enneaedocysta pectiniformis complex, Deflandrea spp., Glaphyrocysta group, and terrestrial palynomorphs including Compositae (tubuliflorae type), Slowakipollenites hipophäeoides, Mediocolpopollis compactus Monoporopollenites gramineoides, Umbelliferae, Periporopollenites multiporatus, Ephedripites sp., Cicatricosisporites sp., Lusatisporites perinatus, Cingulatisporites spp. and Saxosporis sp. comprise the main palynological elements of the Rupelian deposits. Combined information from all three disciplines (terrestrial/marine palynomorphs and sedimentary organic matter, nannoplankton, and foraminifers) suggests that Rupelian sedimentation in the studied sections was characterized by an initial fresh water phase and continued with deposition in shallow to deep marine environments. Although the marine Eocene-Oligocene transition has not been observed in the studied sections, the presence of transitional marine Upper Eocene and Lower Oligocene successions in the northern regions (Cat, SW of Erzurum) as documented by Sancay (2005) suggests that the boundary between the Upper Eocene and Lower Oligocene sediments could have been comformable in some localities of the Mus Basin. However, this argument still needs to be tested where the appropriate lithologies, with recoverable microfossils, are present in the transitional interval in the basin.