Between June 1984 and January 1986, 155 carotid endarterectomies were performed with routine shunting. Serial duplex scanning was performed during an 18-month period on 124 vessels. The results of this duplex scan review revealed the following data: A normal scan was obtained in 87/124 (70.1%). Recurrent stenosis was identified in 35/124 (28.1%), and an occluded vessel was identified in 2/124 (1.6%). Of the total recurrent stenosis group, recurrent stenosis was graded mild in 22/124 (17.7%), moderate in 7/124 (5.6%), and severe in 6/124 (4.8%). Of the 35 vessels with recurrent stenosis by duplex scanning, 22/35 (62.8%) were in female patients, and 13/35 (37.2%) were in male patients. Of the vessels with severe recurrent stenosis, 5/6 (83%) were in female patients. Recurrent stenosis following carotid endarterectomy is more common than appreciated clinically, and female patients in particular may be more prone to recurrent stenosis.