A new genus and species, Chelantermedia composita sp. nov., and five new species of Desmosomatidae Sars, 1897 (Paradesmosoma australis sp. nov., Oecidiobranchus nowrae sp. nov., Disparella kensleyi sp. nov., Whoia victoriensis sp. nov., Echinopleura cephalomagna sp. nov.) are described from the deep sea off south-eastern Australia. The species of Desmosomatidae sampled in 1988 are the first record of this family in Australian waters.