[en] The present paper discusses the use of venturi flow meters for measurement of vapor quality of helium two-phase flow. Tests were performed by connecting two identical venturis with 2.29 mm throat and 4.57 mm inlet diameters in series with a vertical two-phase helium flow loop. With one venturi operating in liquid and the second one operating in two-phase regime as controlled by an inline heater, the ratio of the pressure drop across the two venturis is found to be well correlated to the vapor quality of the two-phase flow. Data presented are for vertical upflow of two-phase helium at 4.2 K with vapor quality between zero and 100% under both forced flow and natural circulating flow conditions. The forced flow rates, controlled by a flexible bellows acting as a positive displacement pump, range from 1.0 g/s up to 2.5 g/s. Within the parameter range covered in this test, the result can be well described by the homogeneous model