The available data on Pliocene-Quaternary planktonic foraminifers from different sites of Legs 4, 41, 45, 46, and 47 DSDP were analyzed. Foraminifer assemblages from equatorial, tropical, and southern subtropical belts were distinguished and compared. In these regions, the single zonal biostratigraphic scheme of H. Bolli (1985) was used. It includes the zones Globorotalia margaritae margaritae, Globorotalia margaritae evoluta, Globorotalia miocenica, Globorotalia tosaensis, Globorotalia truncatulinoides. The latter includes the subzones Globorotalia crassaformis viola, Globorotalia crassaformis hessi, Globigerina calida calida, Globigerina bermudezi, Globorotalia fimbriata. Paleoenvironments of the studied regions were strongly complicated by cold currents and upwelling near the eastern continental margin, which resulted in the formation of strongly variable taxonomic composition of foram assemblages. Frequently the evolutionary datum planes were replaced by local levels of the foraminifer appearance and disappearance. The stratigraphic ranges of species are often interrupted, and this demands the consideration of the total taxonomic composition of an assemblage in order to distinguish correctly biostratigraphic zones.