The incidence of significant restenosis after carotid endarterectomy was studied with ocular pneumoplethysmography. Of 105 operations, symptomatic restenosis occurred in 4.8 percent and asymptomatic restenosis in 6.6 percent. No preoperative factors were identified to be associated with subsequent recurrence. However, technical problems with the end-point of the endarterectomy were associated with restenosis. Half of the restenoses occurred in the first 6 months of operation. The results focus on the need for special attention to the technical management of end-point problems and the need for early noninvasive follow-up to detect a substantial proportion of early restenoses.