A method for operating a magnetoinductive flowmeter of the type including a measuring tube through which flows an electrically conductive medium, at least two electrodes that are in direct conductive contact with the medium, and at least one magnetic field coil that serves to generate a magnetic field which permeates at least part of the medium and in which a predefined current is impressed between two electrodes that are in wet contact with the flowing medium, the voltage present between the two electrodes or between one of the two electrodes and another electrode that is in wet contact with the flowing medium is measured, and a resistance value is derived from the ratio of the impressed current to the measured voltage. This permits the determination and read-out of the conductivity of the medium flowing through the measuring tube, which constitutes an added benefit for the user of the magnetoinductive flowmeter.