The aim of this chapter is to partially update the information about the glaciations and climatic conditions that occurred in Patagonia since the Miocene and to correlate them with the Pampean region and its biostratigraphic scheme. This is one of the most complete sequences in the Southern Hemisphere and records glaciations beginning 7–5 Ma, the Great Patagonian Glaciation (GPG) around 1 Ma, and numerous subsequent cycles. These fluctuations were the primary driver of environmental evolution, forcing ecosystem displacements and recurring faunal interchange, whereby Patagonian species were replaced by Brazilian ones during warmer periods. Ultimately, this led to megafauna extinctions. These climate shifts also shaped the Pampean loess sequences and influenced the early human settlement of the region. Overall, this study provides a vital framework for comprehending the paleobiogeographical and climatic forces that have transformed southernmost South America over the last seven million years.