As part of the AMAPPS (Atlantic Marine Assessment Program for Protected Species) project, the Northeast Fisheries Science Center (NEFSC) and Southeast Fisheries Science Center (SEFSC) of NOAA Fisheries Service conducted line-transect aerial and shipboard abundance surveys to estimate the abundance of cetaceans and sea turtles in the northwestern Atlantic Ocean during Jun–Aug 2011. This manuscript focuses on abundance estimates of cetaceans detected during the NEFSC surveys that covered waters from North Carolina to the lower Bay of Fundy, from the shore to the Gulf Stream, which is about 370 km (200 nmi) offshore. In a study area of about 463,000 km2, over 9100 km of track lines were covered. To estimate abundance the two-independent team data-collection method and the mark-recapture distance sampling (MRDS) and multiple covariate distance sampling (MCDS) analysis methods were used. Overall, approximately 342,000 cetaceans of 18 species were estimated to be present in the study area. Species specific abundance estimates for the surveyed area range from 300–400 sei whales (Balaenoptera borealis) and humpback whales (Megaptera novaeangliae) each, to over 40,000 animals per species of harbor porpoises (Phocoena phocoena), Atlantic white-sided dolphins (Lagenorhynchus acutus), striped dolphins (Stenella coeruleoalba) and short-beaked common dolphins (Delphinus delphis). The abundance estimates of species that also reside south of the NEFSC survey area will be updated when the SEFSC abundance estimates are available.