A new family of polychaetous annelids is described. This family belongs in the order Spionida and is most closely related to the Spionidae. Members of this family have been reported from deep waters off Oregon USA, northeast South America, and southern California (new record). Two genera are presently known for the new family: Uncopherusa (reassigned) and Uncispio gen. nov.; U. hartmanae sp. nov. is described.