Routine intraoperative imaging of the carotid artery following carotid endarterectomy can detect defects at the site of endarterectomy that may lead to neurologic morbidity. A number of methods have been used to evaluate the completed endarterectomy. In this prospective study we compared subjective methods of assessment (hand-held, continuous-wave Doppler imaging with audible interpretation of signals) and objective methods of assessment (duplex ultrasonography with color flow and digital subtraction arteriography) with respect to their ability to detect operative abnormalities. Fifty-three carotid endarterectomies were evaluated by means of all methods of assessment. Six patients had significant abnormalities in which the vessel was reopened and the abnormality confirmed. The sensitivity and specificity for detecting abnormalities for each method are, respectively: duplex ultrasonography with color flow, 100% and 100%; digital subtraction arteriography, 66% and 95.7%; and continuous-wave Doppler imaging with audible interpretation of signals, 16% and 97.8%. There was one (1.8%) operative carotid neurologic complication during the postoperative period and follow-up (stroke due to vein patch rupture on postoperative day 2). These data suggest that an objective rather than a subjective method of assessing carotid endarterectomy is more useful in detecting operative abnormalities and that duplex ultrasonography with color flow is as useful as digital subtraction arteriography.