In order to derive a better understanding of the effect of varying degrees of stenosis on arterial pulsatile waveforms, an in vitro model was constructed and in vivo studies were done in dogs to observe and record the changes in the pulsatile and steady arterial blood flow components. Blood flow measurements were made using the electromagnetic blood flowmeter proximal and distal to the stenosis. The data show that as the degree of stenosis increases, the decreases in the pulsatile components of flow and distal pressure occur earlier and to a much greater degree than changes in mean flow.