Abstract: A method for measuring the velocity of at least a liquid phase and at least a gas phase of a multiphase medium flowing in a volume is disclosed. A first wave is transmitted at a given frequency f1 selected as a function of the liquid phase through at least part of the multiphase medium. At least one parameter, characteristic of a part of the first wave which is disturbed and diffused by the flowing medium is measured. A second wave is transmitted at a given frequency f2 selected as a function of the liquid phase through at least part of the multiphase medium. At least one parameter, characteristic of a part of the second wave which is disturbed and diffused by the flowing medium is measured. At least one measured parameter is processed using the Doppler effect. A velocity field of the liquid phase and/or the gas phase is determined for a given section of the volume in response to the processed at least one parameter.