Six tectono-stratigraphic units have been regionally defined in an area of 12.321 Km2 located towards the marine extension of the eastern Venezuelan basin (i.e. the Deltaic Platform of the Orinoco River). The tectono-stratigraphic units studied are: 1) Cretaceous-Paleogene; 2) Lower Miocene; 3) Middle Miocene; 4) Upper Miocene and 5) Pliocene. Decompacted isopach maps have been generated to determine the original thickness and regional 3D distribution of these tectono-stratigraphic units in the area, and to relate these units to tectonism and sediment supply. The descompacted isopach maps have been produced using thirteen regional 2D seismic reflection profiles previously interpreted and published. The seismic profiles are more than 1500 km long and have been digitised and converted to depth.