We present new Holocene and glacial d 18 O data measured on planktonic foraminifera Neogloboquadrina pachyderma and benthic foraminifera Cibicidoides species from the Atlantic and Pacific sectors of the Southern Ocean in order to better understand its glacial hydrography. Combined with previously published data, the latitudinal d 18 O distributions of these foraminifera show no appreciable difference during the Holocene and the Last Glacial Maximum. This suggests that the basic Southern Ocean hydrography, including stratification and the mean position of the Antarctic Circumpolar Current frontal system, remained largely unchanged, although the small number of Pacific data render any conclusion in that sector preliminary.