Gliomatosis cerebri (GC) is defined as a diffuse neoplastic glial cell infiltration of the brain involving more than two cerebral lobes and, occasionally, the infratentorial structures or the spinal cord. The tumor may appear de novo (primary GC) or result from the spreading of a focal glioma (secondary GC). Diagnosis and management of GC are difficult. Because of the diffuse nature of gliomatosis cerebri (GC), surgery is not suitable and large field radiotherapy carries the risk of severe toxicity.The analysis of current literature shows that the male population (58 percent) is younger, has a higher incidence of oligodendroglial GC and better prognosis than the female population. Survival (median=14.5 months) is also better for young patients, with high performance status, low-grade gliomatosis, and oligodendroglial subtype. Initial chemotherapy results in nearly 30 percent clinical or radiological improvement. In this setting, temozolomide is well tolerated and appears to be a valuable alternative to procarbazine-CCNU-vincristine, especially for slow-growing, low-grade GC.Genotyping could be helpful to predict the response to chemotherapy in GC patients.