This dataset contains occurrence and abundance records of the planktonic foraminifera Neogloboquadrina atlantica sinistral from ODP Site 162-981 and DSDP Site 94-609 in the North Atlantic Ocean. The two sites represent subpolar and transitional oceanographic settings and span the Pliocene to Early Pleistocene interval, a period characterized by progressive Northern Hemisphere cooling and major changes in North Atlantic surface-water circulation. Neogloboquadrina atlantica specimens were identified following the taxonomic concepts of Berggren (1972), and species assignments were verified through scanning electron microscope observations of test ultrastructure following Poore and Berggren (1975). Abundance data are reported as specimens per gram of dry sediment and document variations in the occurrence and abundance of the sinistral morphotype through time.Age control at DSDP Site 94-609 is based on published magnetostratigraphy with updated geomagnetic polarity timescale ages, whereas the chronology of ODP Site 162-981 follows a previously published age model (Lisiecki & Raymo, 2005; Raymo et al., 2004) derived from benthic oxygen isotope stratigraphy and correlation to the LR04 benthic isotope stack. The dataset provides a record of the long-term distribution and persistence of N. atlantica sinistral in the North Atlantic and contributes to the reconstruction of its biostratigraphic range, abundance variability, and regional disappearance during the Late Pliocene-Early Pleistocene climate transition.