ABSTRACT: Assemblages of planktonic foraminifera and dinoflagellate cysts were studied from the 359 m thick Padeha-Baghak composite section of the Abderaz Formation, eastern Koppeh-Dagh Basin, NE Iran. The formation consists mainly of light grey shales and marls with three chalky limestone beds in the upper part. Nine genera and 44 species of planktonic foraminifera and 39 genera and 85 species of dinoflagellate cysts are identified. Planktonic foraminifera are attributed to four biozones (Dicarinella primitiva–Marginotruncana sigali, Dicarinella concavata, Dicarinella asymetrica and Globotruncanita elevata zones). Two dinocyst superzones (Conosphaeridium striatoconum Superzone and the lower part of the Odontochitina porifera Superzone) with seven interval zones are recognized. These biozones suggest a late Turonian–early Campanian age for the Abderaz Formation in this part of the Koppeh-Dagh Basin.