A novel ultrasonic flow metering system been developed that has the capability of measuring liquid film thicknesses of the order of 0.1 mm and mist contents in gas flow of 4-5%. The principle of this nonintrusive technique is based on recording the transit time and attenuation of ultrasonic signals in both axial and radial directions using sets of upto eight transducers flush-mounted on the outside pipe wall at intervals around the pipe circumference and at two locations along the pipeline. The data from the meter is then used in existing multiphase flow models developed at the Corrosion in Multiphase Systems Center, to predict the quality of the gas and flow rate of the individual phases as a function of time.