Continuous deep-scattering layers have been observed in the Irminger Sea for many years. Acoustic observations were carried out during the O-group surveys in the Irminger Sea, in August, in the years 1993–1995. In this paper, the distribution and relative abundance of component organisms based on acoustic values is presented. The layers are observed within the range of 400-500 m to 700-800 m depth. Diurnal migrations of a part of the layers are described. The layers consist of a great variety of organisms. The known components are mainly diverse species offish of which an overview is given. Regional differences are outlined.