Integrated Ocean Drilling Program Expedition 320 cored six sites and 16 holes (Sites U1331-U1336) as part of the Pacific equatorial age transect, recovering a virtually complete composite section ranging from upper Pleistocene to lower Eocene. In general, the successions comprise abyssal biogenic sediments with nannofossil- and radiolarian-ooze end members. Stratigraphic highlights include recovery of richly nannofossiliferous Oligocene successions and complete Eocene/Oligocene and Oligocene/Miocene boundaries at four sites: U1331 through U1334 and U1332 through U1336, respectively. Here, we present a taxonomic overview of the Paleogene nannofossil assemblages from Sites U1331-1334, illustrating 163 taxa and including the description of 11 new species (Reticulofenestra moorei, Reticulofenestra westerholdii, Coccolithus scheri, Cruciplacolithus? klausii, Calcidiscus? edgariae, Calcidiscus? ka-mikurii, Helicosphaera robinsoniae, Pedinocyclus gibbsiae, Discoaster williamsii, Sphenolithus kempii, Sphenolithus richteri, Sphenolithus peartiae) and two new combinations (Calcidiscus? detectus, Coccolithus biparteoperculatus).