Within the Cenozoic sedimentary section of the Roer Valley Graben ten seismostratigraphic units have been identified. They are closely related to the lithological framework which makes it possible to recognize diem also on well logs in this region. The Lower Tertiary seismic units, representing mainly marine sediments, have a uniform development mat can be correlated over large distances into the German part of the Roer Valley Graben. The marine to continental Upper Tertiary and Quaternary seismic units display a more complex development due to lateral facies changes (including prograding delta systems) and rift tectonics.