Abstract99 species of Peracarid Crustaceans (2 Mysidacea, 52 Amphipoda, 28 Cumacea, 15 Isopoda, and 2 Tanaidacea) were identified during a sampling performed on the muddy bottoms of the deep slope in front of Barcelona (western Mediterranean). Ten deep-water samples were performed between 552-1808 m using a small plankton net attached to a bottom trawl. Fifteen species should be considered as Mediterranean endemics: Ampelisca cf. anophthalma, Ampelisca dalmatina, Carangoliopsis spinulosa, Urothoe corsica, Lilljeborgia psaltrica, Idunella pirata, Bathymedon banyulsensis, Oediceropsis pilosa, Pardaliscoides stebbingi, Syrrhoe angulipes, Janirella bonnieri, Fageapseudes retusifrons, Diastyloides carpinei, Diastylis jonesi, and Makrokylindrus stebbingi, while 9 other species were recorded for the first time in the Mediterranean: Epimeria parasitica, Rhachotropis gracilis, Andaniexis abyssi, Chelator insignis, Desmosoma lineare, Belonectes parvus, Munnopsurus atlanticus, Ilyarachna longicornis, and Janirella nanseni. On the upper middle slope amphipods were the dominant taxa both in terms of species richness and abundance. Cumaceans were progressively more abundant when depth increased, being the dominant taxa on the lower slope. All these trends were discussed in the light of the sampling method used and in function of the ecological factors characterizing the deep bathyal environment in the Catalan Sea.