Considerable work on deep-sea parasite faunas, including monogeneans, has been carried out in the north-west Atlantic (Suydam, 1971; Campbell, Haedrich & Munroe, 1980; Munroe, Campbell & Zwerner 1981; Zubchenko, 1981) and some in the Pacific (Gusev, 1957; Robinson, 1961), but work of this nature in the north-east Atlantic is limited mainly to species lists and descriptions (Gallien, 1937; Rees & Llewellyn, 1941; Brinkmann, 1952). The present paper presents observations on monogenean parasites of fishes from the Rockall Trough area of the north-east Atlantic