In order to reconstruct sea surface water productivity and sea floor oxygenation during late Campanian-Maastrichtian, planktonic and benthic foraminiferal assemblages, and organofacies, studies were carried out on a succession of strata in west of Kopeh-Dagh basin of northeastern Iran. Six distinct planktonic (P-types 1–6) and five benthic foraminiferal assemblages (B-types1–5) and five organic assemblages (O-types 1–5) were distinguished in the studied sequence. The changes in composition of assemblages along the section are correlated with variations in surface productivity and water aeration. The changes indicate transition from mesotrophic to oligotrophic conditions.