This master thesis was executed on an existing test rig for small radial pumps at the Vienna University of Technology's Institute for Energy Systems and Thermodynamics. The test rig is situated at the institute's hydrodynamic laboratory. The core were to alter the test rig in a way to make cavitation examinations feasible and, furthermore, conduct an experimental study with it. During the alteration process the test rig was transformed from an open circuit into a closed system. This alteration was necessary to enable a variation of the suction head and, therefore, the static pressure on the suction side of the hydraulic machine. This pressure regulation is essential for cavitation experiments. In the course of the experimental study the pump performance curves for two different runners were measured and evaluated. The head curves, NPSH curves, efficiency curves and shaft power curves were measured for different speeds. Given that the water-bearing elements of the hydraulic machine are mostly made of acrylic glass, it was, furthermore, possible to conduct an optical examination of the occurring cavitation phenomenon. The examined runners have similar main dimensions. Only one has a slightly different blade design (i.e.: advanced leading edge and double curvature blades), which should in theory lead to better cavitation characteristics. These improved cavitation characteristics were presented in detail by, on the one hand, comparing the pump performance curves of both runners and, on the other hand, comparing the results from the optical examinations. The findings of this master thesis offer insights into the cavitation characteristics of the two runners and, furthermore, the possibilities and limitations of the test rig¿s basic setup.