Objectives: To determine the incidence of restenosis after carotid endarterectomy (CEA), as well as to observe its natural history and identify the risk factors for its development. Material and methods: Retrospective study of a prospective cohort of CEA performed in 20062011 The variables recorded were: clinical data, surgical details, incidence of moderate restenosis (MRE) (50-69%), severe restenosis (SRE) (>= 70%), and occlusion. The patients were followed-up with carotid duplex-scan 6, 12, 18 and 24 months after the procedure, and annually thereafter if MRE/SRE was found. All SRE were confirmed with MRI. No restenosis was surgically or endovascularly repaired. A descriptive analysis was performed, and Chi-squared/Fisher's exact test was used for the definition of SRE risk factors. Results: A total of 186 patients with carotid endarterectomy were included, 77 (41.4%) performed in symptomatic patients, and a patch (dacron) used in 19 (10.2%) cases. During the first year of follow-up 20 (10.8%) MRE were found, with 9 of them (45%) regressed (to <50%) and one (5%) progressed to SRE during the second year. SRE was observed in 12 (6.5%) patients during the first year of follow-up, and 4 (33.3%) regressed (to 50-69%) during the second year, and 3 (25%) more during the third year. No SRE were occluded or became symptomatic. Two carotid arteries became occluded during the first year (one caused a stroke), and one more during the second year, without previous >= 50% restenosis. The use of Kunlin stitches increased the risk of developing SRE (OR 3,61; 95%Cl: 1.13-11.57; P=.023). Conclusions: SRE after CEA, mostly with direct suture, is infrequent. The natural history of SRE during follow-up is benign. Kunlin stitches are associated to the development of SRE. (C) 2014 SEACV. Published by Elsevier Espana, S.L.U. All rights reserved.