With development of novel and highly differentiated therapeutic strategies in neuro-oncology, the role of the pathologist as a member of the multidisciplinary neuro-oncology them became central and earries even greater responsibility. It is on the basis of the pathologic diagnosis that critical inferences about the natural history and prognosis of the disease are made and treatment plans, often including radiation and chemotherapy, follow. Proper classification and grading of brain tumors become essential in speaking a common language and avoiding, potentially dangerous misunderstandings.1 This particularly applies to gliomas, the most common primary brain tumors, which comprise a large spectrum of neoplasms with extremely different natural history, biologic aggressiveness., and prognosis. Rigid adherence to a diagnostic algorithm, which takes into Account characteristic; clinical, neuroimaging, and pathologic features is essential. In the present article, we will focus on classification and grading criteria of diffuse gliomas, comprising astrocytic, oligodcndroglial, and mixed neoplasms, aiming to yield a simple, precise, and unequivocal tumor designation.