The need to increase understanding of the impacts of changing natural and anthropogenic drivers on hydrological processes on local and regional scales is an essential prerequisite for advancing hydrology and a precondition for solving water resources management tasks. Slovakia exhibits abundant spatial and temporal variability of hydrological processes complicating the generalisation of runoff regimes. Changing climate and recent extreme floods and droughts put additional pressure on improving the observing, monitoring, describing, and modelling of hydrological processes. This paper reviews the response of hydrologic research in Slovakia to these challenges published in international journals from 2019 to 2022. It continues the practice of publishing the review part of the Slovak National Reports to IUGG on behalf of the IAHS (Szolgay, 2003;2007;, which follows the custom of National IUGG Committees to prepare a Quadrennial Report for the IUGG General Assemblies containing comprehensive summaries of national activities in geodesy and geophysics (Szolgay, et al., 2023).