Twenty-one outcrop samples collected from a 28-m-thick section from the Safranbolu Formation of the southwestern part of the Safranbolu Basin, Anatolia, Turkey yielded well-preserved benthic foraminifera belonging mainly to the genera Alveolina, Nummulites, Assilina, Rotalia, Disclocyclina and Orbitolites. Alveolina is the most diversified genus that is represented by sixteen species: Alveolina archiaci, A. axiampla, A. barattoloi, A. carantana, A. colatiensis, A. cuspidata, A. distefanoi, A. histrica, A. lehneri, A. oblonga, A. polatliensis, A. rakoveci gueroli, A. ruetimeyeri, A. rugosa, A. safranboluensis and A. sirelii. Alveolina safranboluensis and A. sirelii are described new. Comparison of the fossil assemblage with those assemblages previously reported from both Turkey and other Tethyan sub-basins revealed that the deposition occurred during the Cuisian (Eocene) and corresponded to Shallow Benthic Foraminiferal Zones (SBFZ) 10–12. The abundance and diversity of the larger benthic foraminifera indicated that the Safranbolu Formation was deposited under transgressive conditions.