Objective. To clarify the indications for deconstructive endovascular surgery in patients with large and giant intracranial aneurysms and to evaluate short-term and long-term postoperative outcomes. Material and methods. The study was based on a retrospective analysis of the treatment results in 50 patients with large (15―25 mm) and giant (more than 25 mm) intracranial aneurysms, aged from 18 to 75 years, who were treated at the Burdenko Neurosurgical Institute in 2002―2014. The patients underwent a balloon occlusion test (BOT) in various modifications before stationary occlusion of the carrier artery. For vascular occlusion, we used detachable latex balloon catheters (33 cases) and microcoils (17 cases). The condition of patients in the pre- and postoperative period was assessed by using the modified Rankin Scale. Results. There were no deaths due to occlusion of the internal carotid artery (37 patients). Postoperative complications occurred in 5 patients. On the basis of BOT, revascularization surgery involving placement of an extra-intracranial microanastomosis (EICMA) was performed in 6 cases. In more 4 cases, EICMA was placed in the early postoperative period due to developing signs of ischemia. Two of 7 patients underwent occlusion of both vertebral arteries (VAs) in the vertebrobasilar basin, which led to fatal outcomes. One more patient died of aggravation of brainstem compression after VA occlusion. There was no worsening of neurological symptoms among survivors. There were no deaths and persistent neurological disorders upon occlusion of branches of the main cerebral arteries, starting with the first order arteries (6 patients). Thirty one patients (66%) were followed-up in the period from 1 to 104 months. There were no deaths associated with artery occlusion. Two patients experienced delayed ischemic disorders. Conclusion. Occlusion of the carrier artery should be performed in a carefully selected group of BOT-negative patients. This surgery can be indicated for aneurysms with a complicated configuration, the topographic and anatomical features of which exclude reconstructive surgery.