92 species of planktonic ostracods were identified from five total water column samples of macroplankton collected from the surface to depths of 5000 m in the northwest subtropical Atlantic. Thirteen of these species are either totally novel or previously undescribed. This brings the total inventory of planktonic ostracods known from this region to118 species, and for the whole Atlantic to 153. All but one of the undescribed species were collected from depths 41000 m. This region is already the most comprehensively studied in the global ocean for plankonic ostracods. Similar studies conducted in other less well studied regions particularly in the Pacific and Indian Oceans will reveal far higher numbers of novel species.