A simplified technic utilizing the ultrasonic directional flowmeter for the detection of hemodynamically significant aortoiliac obstruction is described. The method is based upon the presence of a reversed flow pattern along the inferior epigastric artery in patients with aortoiliac obstruction. Correlation with angiographic findings was made in the twenty patients reported on in this study. In twelve patients with severe or complete iliac artery obstruction, reverse epigastric flow was present, whereas in the remaining eight without significant obstruction to arterial flow, the inferior epigastric arterial flow direction remained normal. © 1979.