An experimental study of flow in a Francis hydraulic turbine, especially designed for the GAMM Workshop, has been carried out. In order to provide a data base for the validation and comparison of computational fluid dynamics codes, a Francis turbine mode! and adequate instrumentation have been specially developed. Measurements of both global and local quantities have been performed for the best operating point of the turbine. A five-hole probe mounted on a remote traversing system provides static pressure and velocity components along three measurement axes in the machine. Pressure transducers mounted on the pressure and suction sides of the rotating blades of the runner provide the pressure distribution over the blades in 28 points (17 on the suction side and 11 on the pressure side) arranged along three theoretical streamlines.