A method and system are provided for estimating velocity of flow within an ultrasound dataset. A sample volume gate is defined on a two-dimensional (2D) image. The 2D image is based on an ultrasonic dataset. Spectral Doppler velocity estimates of flow are detected within the sample volume gate in first and second dimensions that are orthogonal with respect to each other. A true velocity estimate of the flow within the sample volume gate is determined based on the Doppler velocity estimates.