Four new species belonging to the families Eunicidae and Onuphidae are described on the basis of specimens collected from El Salvador, Central America. Additionally ten species belonging to Onuphidae are mentioned, nine of these are newly reported from El Salvador. Eunice chicasi sp. nov., belong to the group of species with acicula distally hammer head, peristomial cirri smooth only reaching middle peristomium, branchiae from chaetiger 5 to the end of body, with up to six filaments, falcigers with lateral tooth triangular, well developed. Eunice salvadorensis sp. nov. has moniliform and cylindrical articles in the antennae, peristomial cirri with 17 small moniliform articles. Kinbergonuphis kristiani sp. nov. presents up to ten branchial filaments, ventral cirri digitiform on the first seven chaetigers, pseudocompound hooks tridentate appear on chaetigers 1–5, large tridentate hooks on chaetigers 5–7, and subacicular hooks from chaetiger 19. Paradiopatra barrazai sp. nov. belongs to the group of species with inner lateral antennae longer than the median antennae, ceratophores with four rings, ventral cirri of chaetigers 1–2 cirriform, postchaetal lobe digitate visible to the end of the body, tridentate pseudocompound hooks on chaetigers 1–4, large tridentate hook on chaetigers 5–28, subacicular hooks from chaetiger 30.