Volumetric blood flow measurements require the assessment of both the velocity distribution and the cross-sectional area of the vessel. Unfortunately several difficulties hamper such a measurement in standard approaches. A new dual beam method has been recently introduced in which the Doppler spectral symmetry is exploited to finely orientating the first beam at 90?? with respect to the flow, so that the remaining beam can perform a velocity measurement with known Doppler angle. In this paper it is shown how this special beam configuration proves particularly suitable for volume flow measurements. While the transverse beam performs a diameter measurement with optimal orientation, the velocity distribution along the second beam is measured through multigate spectral analysis. The method has been coded on a research system. In-vitro experiments produced a bias less then 7% with a coefficient of variability (CV) less then 5%. In preliminary tests on 3 volunteers CVs within 10% were obtained.