Over 6,000 polychaete worms belonging to 229 species were collected on a transect running from the sandy shore near Beaufort. N.C., to the upper part of the continental slope in 200 m. Eleven more species were collected from the shores of Beaufort Sound and from grab samples in 400, 600, and 3,020 m off North Carolina. The whole collection includes 19 new species, 2 new subspecies, and 16 new records for the United States. These have been described. An examination of the literature revealed that a further 83 species had been recorded by earlier workers so that a total of 323 species of polychaete worms are now known from North Carolina. Keys have been constructed to cover the whole fauna, all original records have been listed, and references to good descriptions of each species are given. During the course of the work several type specimens were examined and this has resulted in certain changes in nomenclature and the redefinition of certain genera in the families Orbiniidae, Flabelligeridae, and Ampharetidae.