Eurysyllis Ehlers, 1864 is a syllid genus currently comprising seven species, of which members are characterized by a relatively small, dorso-ventrally flattened body, with the dorsum covered by longitudinal rows of tubercles, and appendages (i.e., antennae, peristomial and dorsal cirri throughout) composed of a single article each. The analysis of the material collected off the southeastern Brazilian coast resulted in the identification of three new species of
Eurysyllis, which also represent the first record of the genus off Brazil. The new species differ from each other and from their congeners in details of the shape of tubercles, number of eyes, and morphology of falcigers. These three new species are herein described and compared to their most similar congeners; a key for the identification of all species of
Eurysyllis is provided.