The electrochemical cavitation detection technique has been used to locate and measure the instantaneous cavitation erosion rate on a 2D NACA profile tested in the IMHEF high-speed cavitation tunnel. Nineteen titanium probes, flush mounted along the profile suction side could monitor during the test thee local and instantaneous erosion rate with a detection limit as low as 0 .02 mm per year of titanium grade 2. Pressure measurements have been also made as well as high-speed photography. The operating condions has been varied in a wide range of velocity, flow incidence and cavitation number. Maximum erosion rate is located in the closure region of the main cavity and is at its highest level for highest cavitation number values compatible with the onset of a leading edge fluctuating cavity. Erosion was associated with the collapse of large transient swirling cavities. These experiments can help to elucidate the basic mechanism responsible for the high cavitation erosion rates observed in large hydraulic machines.