The area under investigation is located within 22°45' to 23°45'E, and from 39°15' to 40°15'N. Sedimentological, bathymetric and shallow geophysical data were collected from here during the 7/78 cruise of R.R.S. "Shackleton". Twenty-seven sea-bed (surface) samples were collected, using a Day grab, from different environments; these were analysed for grain-size distribution, carbonate content, and clay mineralogy.On the basis of the bathymetric and shallow geophysical data, the area has been classified into five major physiographic environments, according to their bathymetry and topography: (1) shelf (Thermaicon Plateau); (2) slope; (3) marginal plateau; (4) the "canyon system" and valleys; and (5) (Sporades) basin.Based on the sedimentological analyses, the surface sediments have been classified into four major Provinces, as follows: (1) Province 1 - shelf muds; (2) Province 2 - muddy sands; (3) Province 3 - outer margin muds; and (4) Province 4 - outer shelf/shelf break.It is concluded that modern sedimentation in the N.W. Aegean Sea is dominated by the (terrigenous) river inputs and by the circulation of both high and low salinity masses.