Calcareous nannoplankton from 44 samples of a thick Neogene sequence of site 516 in the South Atlantic was examined. Paleoecological analysis of more than 60 nannofossil species allowed us to prove that the formation of the Neogene sedimentary sequence proceeded under tropical conditions with a variable regime of the surface water temperature. Relatively stable warm-water conditions were characteristic of the Early Miocene; during the rest of the Miocene, warm-water, though variable, conditions were observed, while in the end of the Miocene-beginning of the Pliocene, the environment was variable and mostly cold-water. Subsequently, the conditions became quieter with a gradual enhancement of the near-bottom environment.