Objective. To compare in-hospital and mid-term outcomes of conventional carotid endarterectomy (CEE) followed by patch angioplasty with diepoxy-treated xenopericardium in patients with bilateral and unilateral stenoses of the internal carotid arteries (ICA). Material and methods. The study included 513 patients who underwent conventional CEE. Bilateral significant ICA lesion were diagnosed in 29.4% (n=151) of patients (the first group). Patients with contralateral ICA lesions were followed-up within 13.8±6.7 months, patients with unilateral stenosis (the second group) — 15.1±6.3 months. Incidence and causes of mortality, ischemic stroke, myocardial infarction (MI), thrombosis/restenosis within in-hospital and mid-term postoperative period were analyzed. Results. Clinical and instrumental characteristics were comparable in both groups. Significant coronary artery stenoses were diagnosed in 25% of patients. Therefore, hybrid treatment (percutaneous coronary intervention + CEE) was performed in 20.6% (n=48) of patients. In-hospital outcomes were similar in both groups. In the group of bilateral stenosis, ischemic stroke was recorded in 2% of patients vs. 3% in the second group (p=0.5), MI — in 0.6% vs. 1.1% in the second group (p=0.97), mortality rate was 1.3% vs. 0.3% in the second group (p=0.43), laryngeal paresis developed in 6.6% of patients vs. 5.5% in the second group (p=0.78), post-intubation pharyngitis — 4.6% vs. 5.8% in the second group (p=0.75), acute hematoma — 0.6% vs. 0.8% in the second group (p=0.72). Mid-term mortality significantly differed in both groups. Other variables were comparable. In the group of bilateral stenosis, ischemic stroke was recorded in 2.6% of patients vs. 1.6% in the second group (p=0.69), MI — 1.3% vs. 3.6% in the second group (p=0,27), laryngeal paresis — 6.6% vs. 5.5% in the second group (p=0.78). Conclusion. Similar in-hospital morbidity and higher mid-term postoperative mortality after conventional CEE are confirmed. The absence of wound infection and postoperative thrombosis/restenosis of reconstruction zone demonstrates the effectiveness of diepoxy-treated xenopericardium patch in carotid surgery.