Aortoiliac obstructive disease was assessed by Doppler spectrum analysis of blood flow velocities in the common femoral artery measured both at rest and during reactive hyperemia. The intraarterial femoral artery pressure measured at rest and during reactive hyperemia served as the "gold standard" for the definition of a hemodynamically significant aortoiliac stenosis. Our results, obtained from 93 patients (136 limbs), showed that differences between Doppler spectra obtained from limbs with a hemodynamically significant aortoiliac stenosis and those from limbs without were more pronounced during reactive hyperemia than at rest. The best assessment of aortoiliac obstructive disease could be obtained with a combination of parameters derived from Doppler spectra measured at rest and during reactive hyperemia. With these parameters, obtained by multivariate analysis, 85% of the limbs were diagnosed correctly compared with the gold standard. If angiographic data were added to the gold standard, even 91% of the limbs were diagnosed correctly. We conclude that analysis of Doppler spectra-obtained noninvasively from the common femoral artery at rest and during reactive hyperemia provides an accurate hemodynamic assessment of the aortoiliac segment.