The NW Peloponnese (Greece) belongs to the west-verging Alpine thrust-fault belt. Deep-water sedimentation ensued, in the Gavrovo-Tripolitza and Ionian foreland basins, as relief was being built-up and the Tertiary compression migrated westwards. The deep-water sedimentation and the deep structure of the thrust-fault belt are hereby assessed on the basis of interpreted seismic profiles, borehole and field data. The sedimentation is controlled by sea-level changes and thrust activity. The highest sedimentation rates for the Gavrovo-Tripolitza and Ionian Zones are observed during the Early Oligocene. In the Late Eocene, within the Gavrovo-Tripolitza Basin, middle to outer fan associations prevailed (Drossia-Charavghi Formation) changing to a channeled sea floor (Roupakia Formation) as the Pindos thrust front approached. A deceleration of the Pindos’ advancement, combined with sea deepening, changed the environment to distal fan and hemi pelagic (lower Skouras Formation). On top of the Skouras Formation a regressive episode is marked. In Late Eocene, clastic sedimentation was installed in the Ionian Basin. First, distal fan facies overwhelmed the Ionian carbonate sedimentation (Mavri Miti Formation). In the Early Oligocene the Santameri Formation witnesses basin stability with distal characteristics in its lower parts. The lower Peta Formation, during the Late Oligocene is similar to the previous one. A rapid and important uplift of the Pindos hinterland is marked in Peta’s upper members.