Background. Diagnostics of malignant brain tumors is one of the most difficult problems in medicine as well as in neuropathology. The old WHO classification (before 2016) is primitive and far-fetched, based on surface rather than essential principles. New WHO classification (revised fourth edition) was published in the first half of 2016. Now we have new and changed names, changed ranges of diagnostic entities with unknown clinical and pathological features. Moreover, it is known, we are at the intermediate stage of natural classification development. Nevertheless, first and main step is done and neuropathology has entered in molecular era irretrievably. Objective. The aim of this study was to analyze literature data on the brain astrocytic tumors classification, and to develop a strategy of diagnostic search, based on the revision of the fourth edition WHO classification of central nervous system tumors. Results and conclusion. The authors present and analyze changes in diagnostic categories as well as their location, propose new diagnostic algorithms according to current classification. The proposed scheme includes immunohistochemistry for mutant isocitrate dehydrogenase-1 (IDH1) and, if indicated, the investigation of gene IDH2 mutations, involving a method of sequencing. The work will be of interest to teachers of the course “Pathomorphology” in system of higher medical education (theme: "Tumours of the nervous and melanin-synthesizing system"), pathologists and neurosurgeons.