The family Polychelidae includes thirty-eight species of blind deep-sea lobsters distributed in six genera. Five species are recorded from the south-western Atlantic region: Pentacheles laevis; Pentacheles validus; Polycheles typhlops; Stereomastis sculpta; and Willemoesia forceps. Herein we analysed material sampled in deep Brazilian waters adding the first record of Stereomastis nana to the south-western Atlantic region. An identification key to all south-western Atlantic polychelids is provided.
