Polychaetes of the family Cirratulidae are common components of the benthic fauna of the northeastern United States. Although several species have been treated by Blake (1991), the true diversity of northeastern Atlantic cirratulids is underestimated since species remain largely undescribed or are erroneously assigned european names. The present paper provides descriptions of three new species of Chaetozone and one new species of Caulleriella. All four of these taxa were collected as part of environmental monitoring programmes in Long Island Sound, Boston Harbor, Massachusetts Bay, and/or Georges Bank from depths ranging from 10 to 200 m. In addition to traditional observations, details provided by the Scanning Electron Microscope (SEM) and staining patterns revealed by Methyl Green are used to further define these taxa and to distinguish them from congeners. Formal descriptions of these new taxa will contribute to a larger understanding of the systematics and interrelationships of the bitentaculate Cirratulidae.