Patterns of fluid flow are investigated by a technique utilizing NMR spin echoes. Spin‐echo amplitudes are sensitive to the phase distribution of the resonating nuclei in the fluid, and the phase distribution is dependent upon the flow. A mathematical transformation of the spin‐echo amplitudes observed provides a velocity distribution function which indicates the relative number of molecules flowing in any given velocity range when plotted. Experimental data are obtained from ordinary laminar flow, and blood flow in human fingers.