Amphipods are a highly diverse group of aquatic invertebrates with >10,000 described species globally. About 20% of these are freshwater species, with half of them found in the West Palaearctic. Amphipods inhabit almost all freshwater ecosystems, including lakes, rivers, streams, as well as cave and groundwater systems, and can be the dominant macroinvertebrates in these habitats. They exhibit essential roles in the functioning of aquatic ecosystems, contributing to leaf litter breakdown and serving as important prey for fish. Furthermore, they are commonly used as indicator taxa for biomonitoring and in ecotoxicological studies. Many amphipod communities are currently undergoing rapid changes due to various drivers of global change, and some amphipod species are among the most successful nonnative invasive invertebrates. Despite their ecological and economic significance, the knowledge on amphipods in Switzerland was hitherto limited, and until now no checklist, distribution maps, or broadscale estimates on genetic, functional, and morphological diversity of all amphipod species in Switzerland existed. All hitherto available literature on the ecology, faunistics, and taxonomy of amphipods in Central Europe is either outdated by many decades (Chevreux & Fage, 1925; Schellenberg, 1942), does not cover all species (Ginet, 1995; Eggers & Martens, 2001, Piscart & Bollache, 2012), or is only targeting neighboring countries (Vornatscher, 1965; Karaman, 1993; Eggers & Martens, 2001; Piscart & Bollache, 2012, Zettler & Zettler, 2017). This lack of appropriate baseline information on the ecology, distribution and faunistics of amphipods in Switzerland is a serious limitation for fundamental ecological research, impedes appropriate conservation strategies, and limits the use and application of amphipods as indicator taxa.