The genus Euthelepus is redefined, and of the 7 species currently assigned to it only 2 species belong to the genus, plus a newly described species E. serratus n.sp. The remaining species belong either to Thelepus or Streblosoma. A full description of each species is given where necessary, based upon a re-examination of type material. A key to the species of Euthelepus is given. Comments are made upon the validity of some of the characters which have been used traditionally in terebellid taxonomy.