This chapter documents the occurrence of significant hydroclimatic changes and water-lake level fluctuations in the Pampa plain during the twentieth and twenty first centuries. This review provides a picture of the timing, magnitude, spatio-temporal characteristics and causes of the hydrological response of the Pampas lakes to recent changes in the dynamics and intensity of the South American Summer Monsoon. The occurrence of significant hydroclimatic changes and water-lake level fluctuations are evaluated. Different study cases are presented and analysed, allowing a deeper understanding of the mechanisms underlying regional climate variability at different latitudes. Results provide key information for understanding the natural drivers that modulate the high-frequency (seasonal and interannual) and low-frequency (decadal to bidecadal) regional precipitation and hydrological balance changes in the Pampa plain. Our results have important implications for both the interpretation of past water-lake level records and provide clues for predicting future responses of Pampean lakes to climate change.