The hemodynamic significance of stenosis was defined by intraoperative measurement of pressure and flow across 22 profunda femoris and 44 iliac artery segments. Measurements were taken at rest and during papaverine-induced vasodilation, and the mean pressure gradient across the arterial segment at double resting flow was calculated. Profunda femoris artery mean pressure gradients at resting flow were less than or equal to 3 mm Hg for stenoses up to and including 75%. The mean pressure gradient at double resting flow increased significantly in profunda femoris arteries with greater than 60% stenosis and was greater than 10 mm Hg in 7 of 10- profunda femoris arteries with 60% to 70% stenosis. Resting mean iliac artery pressure gradients were less than 10 mm Hg in 38 of 39 arteries with less than 90% stenosis and less than 5 mm Hg in 35 of 39. The mean iliac artery pressure gradient at double resting blood flow exceeded 10 mm Hg in 11 of 12 arteries with greater than 70% stenosis and was greater than 8 mm Hg in all 12. Four of 19 iliac arteries in the range of 20% to 65% stenosis as measured by arteriography had pressure gradients at double resting flow greater than 10 mm Hg. These results indicate that the hemodynamic significance of profunda femoris artery stenosis can be determined by intraoperative measurement of mean pressure gradients at double resting blood flow. Mean iliac artery pressure gradients at double resting blood flow may be useful for estimating the hemodynamic significance of iliac stenosis in situations where angiographic findings show mild-to-moderate iliac stenosis.