Seismic and well-log signatures in the Pliocene-Pleistocene of the northeastern Gulf of Mexico reveal four major slope depositional units. (1) During the Pliocene, slope deposition was influenced by deformation and restructuring of moderately intact, shallowly buried, allochthonous salt sheets. Sediment supply to the slope during this period was characterized almost exclusively by repeated breakup of unstable, shelf-margin deltas. (2) Lower Pleistocene clastic sediment supply to the slope was minimal in response to a major avulsion of the Mississippi River. (3) The middle Pleistocene marked renewed slope sedimentation and was influenced by the slope fabric set up during the Pliocene. This depositional unit also marks the introduction of major erosive canyons, which are no ably absent prior to this time. (4) During the late Pleistocene, slope deposition rates and eustatic amplitude and frequency increased significantly and sediment input to the slope became much less influenced by the distribution of salt. Sediment supply to the slope also became increasingly more focused by canyon development. The recently deposited upper Mississippi fan is the latest stage in this slope evolutionary process.