Objective. To clarify the indications for surgical treatment of malignant cerebellar infarction (CI). Material and methods. Eighty patients with CI were studied. The malignancy of CI was understood as the development of mass effect in the posterior cranial fossa, accompanied by the decrease in consciousness due to compression of the brain stem and/or the development of occlusive hydrocephalus. The patients were divided into 2 groups. The group of malignant CI included 55 patients (68.75%) (group I), the group of benign CI included 25 patients (31.25%) (group II). Patients of group I were divided into subgroups, one of them underwent surgical treatment (surgical subgroup), and another only conservative (conservative subgroup) treatment. Surgery efficacy criteria were: restoration of consciousness to 15 points according to GCS and/or restoration of the fourth ventricle and the quadrigeminal cistern configurations. Results of treatment were assessed according to the Glasgow outcome scale. Results. Malignant CI occurred more frequently in patients with the volume of ischemia exceeding 20 cm3 (p<0.05) in the first day of the disease. The threshold value of mass effect, which can cause further a malignant CI, was 3 points according to the M. Jauss scale. In the group of patients with malignant CI, surgical treatment reduced the mortality rate from occlusion and dislocation syndrome by 35.8%. The most effective type of intervention was a combination of decompressive trepanation of the posterior cranial fossa and external ventricular drainage. Conclusion. In patients with CI with the volume more than 20 cm3 and signs of mass effect in the posterior cranial fossa on the scale of M. Jauss 3 points or more, the malignant course of the disease develops in 67% of cases. These patients require careful monitoring, and, in case of development of malignant CI, surgical treatment is necessary.