The Salado river basin is the largest one in the Buenos Aires province, with an area near 170,000 km2. This work aims to perform a stratigraphic analysis of the middle sector of this basin to provide information on the paleoenvironmental evolution during the end of the Quaternary. Results indicate that the evolution of this basin occurred largely in water deficit conditions. Different aeolian lithostratigraphic units are recognized and grouped into three units, as follows: La Postrera, Laguna Las Barrancas, and De la Riestra Formations. New lithological, paleontological, and chronological information is provided regarding the fluvial deposits, which allows for a deeper understanding of the paleoenvironmental conditions that prevailed during deposition. The integrated study of all these deposits with an adjusted chronological control suggests a paleoenvironmental model that is directly associated with the climatic conditions that prevailed at the end of the Quaternary.