Method and system for localizing a region of interest in a medium in which cavitation occurs. Method for localizing a region of interest (R) in a medium (M) in which cavitation occurs, the method comprising the steps consisting in: producing cavitation in the region of interest (R), the cavitation generating an acoustic signal, at each of at least three separate positions, detecting a cavitation signal representative of the acoustic signal of the cavitation, for at least two pairs of cavitation signals, determining a delay between the cavitation signals of each pair of cavitation signals, calculating a localization of the region of interest (R) based on the delays and the positions.