A group of patients with benign course of massive ischemic stroke (MII) without development of the dislocation syndrome and a group of patients with malignant course with development of the hemispheric brain edema with the following transtentorial herniation were singled out. Risk factors for the development of malignant form of MII and its fatal outcomes were specified as lateral dislocation (>7 mm), more than 70% of ischemia size in frontal and parietal lobes and more than 80% - in temporal lobes, the disturbance of wakefulness up to moderate coma or more. Based on these results, it was selected patients for decompressive craniotomy in the affected hemisphere that allowed to reduce the fatality rate by more than twice compared to patients treated without surgery.