Gliomatosis Cerebri (GC) is defined as a diffuse infiltration of a glial tumor generally astrocytic that involves at least 3 cerebral lobes bilaterally and usually the condition extends to the brainstem. Its incidence represents approximately 1% of all brain tumors and occurs more frequently in young adults. The diagnosis is established from clinical environment, imaging and histological confirmation. The therapeutic possibilities are limited and the survival close to 2 years showing a high mortality. We report the case of an 11-year-old male patient who was treated at the Central Military Hospital of Bogotá, Colombia where the diagnosis was made and treatment was instituted.