In developed countries, atherosclerosis is the major reason for morbidity and mortality. The external carotid artery is an important collateral in atherosclerotic carotid artery disease. Blind endarterectomy is performed to the external carotid artery during carotid endarterectomy surgery. After the surgery performed by this method, a 5-16% occlusion rate in the external carotid artery was reported in the short and long term. The aim is to show the early pathology on the external carotid artery and its clinical importance after standard carotid endarterectomy. In our study, 30 patients who underwent carotid endarterectomy for carotid artery stenosis were recruited in Istanbul University Cerrahpaşa, Department of Cardiovascular Surgery. Twenty-one patients were male and nine females. The mean age was 63.6 (±9.0). Preoperative duplex ultrasonography was performed in all patients. After discharge, during outpatient control FT3, FT4, and TSH were evaluated with blood tests and flow rates with color duplex. Rate evaluation: <50% stenosis if flow rate is <150 cm/s, 50%-75% stenosis if flow rate is between 150-250 cm/s, and >75% stenosis if flow rate is >250 cm/s. In the duplex examination, we did not detect any significant change in flow rates, external carotid artery flow rates in the preoperative and early postoperative period. However, as expected, a significant reduction in the internal carotid artery flow rates after the operation was recorded. In the analysis of thyroid functions, no significant difference was detected between preoperative and postoperative values. Stenosis, occlusion and dissection can be seen on the external carotid artery after carotid endarterectomy. There are no signs or symptoms due to these lesions. Carotid endarterectomy is a safe procedure for external carotid artery and thyroid superior artery and thyroid gland.