Deep benthic communities of the Bay of Biscay (North East Atlantic) have been thoroughly sampled during seven cruises between 1972 and 1974.Some 200 samples using three main types of gear (corer, epibenthic sled and beam trawls) have been performed. Sediment characteristics (granulometry, organic content) and faunal densities for each size assemblage are given.Continental influences appear to increase macrofaunal density.Compared with other areas, the central part of the Bay of Biscay appears to have a low faunal density. This fact can be related to the existence of a mesoscale gyre of the upper layer, which could be responsible for a low primary productivity. [NOT CONTROLLED OCR]