This analysis assesses the impacts of global change on hydrological processes in Alpine catchments. We applied the regional hydroecological simulation system RHESSys to five case studies from different climatic zones in the European Alps. Seven scenarios based on the so-called SRES emission scenarios of the Intergovernmental Panel on Climate Change were used to describe changes in climate and land use. Shifts in runoff regimes and annual and summer runoff were investigated. The focus was on analyzing differences in the hydrological responses of different Alpine climate zones, exploring differences between SRES scenarios (A1FI, A2, B1, and B2), and analyzing the importance of applying several global circulation models (HadCM3, CGCM2, CSIRO2, and PCM). Under all scenarios, rising temperatures were projected to strongly affect runoff regimes via the impact on snow cover. The overall effect is a substantial runoff regime shift across the Alps, with specific differences depending on the climatic zone considered.