The biostratigraphy of the Upper Cretaceous volcanoclastic-sedimentary formations cropping out in the Timok Eruptive Area of the eastern Serbian Carpatho-Balkanides is presented. Four lithostratigraphic units of formation rank are recognized in the Timok area: Stublica Clastics (Upper Albian/Cenomanian), Ostrelj (Lower Turonian/Santonian), Bor Clastics (Campanian/Maastrichtian) and Bukovo (Campanian/?Maastrichtian). Forty two species of planktonic foraminifera have been determined in the studied area. Eight planktonic foraminiferal zones of Middle Cenomanian through Middle Campanian age have been recognized. These are: Thalmanninella reicheli Interval Zone (Middle Cenomanian), Rotalipora cushmani Taxon Range Zone (Upper Cenomanian), Helvetoglobotruncana helvetica Taxon Range Zone (Lower Turonian), Marginotruncana sigali–Dicarinella primitiva Interval Zone (Upper Turonian to lowermost Coniacian), Dicarinella concavata Interval Zone (Lower Coniacian to lowermost Santonian), Dicarinella asymetrica Taxon Range Zone (Santonian), Globotruncanita elevata Interval Zone (Lower Campanian) and the Globotruncana ventricosa Interval Zone (Middle Campanian). The scarcity or lack of zonal species in the Lower Cenomanian and Upper Campanian/Maastrichtian strata prevents recognition of the nominal zones. The Upper Cretaceous planktonic foraminiferal zones from the Timok Eruptive Area are correlated with coeval zones from adjacent regions of Bulgaria and Romania and from other Tethyan regions.