A 49-year-old female patient was admitted due to memory disturbances. Magnetic resonance (MR) imaging suggested gliomatosis cerebri (GC), which had spread to both insular lobes, both frontal and basal ganglia and the brain stem. A stereotactic biopsy was performed at the high signal intensity area of the T2-weighted MR image, and the revealed a diffuse astrocytoma. Radiation therapy was judged not to be an appropriate treatment for the patient because of her cognitive impairment. A combinatorial chemotherapy regiment consisting of Procarbazine, CCNU, and Vincristine (PCV) was agreed upon after discussion. The patient underwent six cycles of PCV chemotherapy (a full dose was applied until the 3rd cycle, and dose then was reduced to 75% for the remaining cycles). Although the patient exhibited side effects such as bone marrow suppression and gastrointestinal symptoms, these were managed by medication. Over the 28 months following initiation of treatment, the high signal area in the right frontal and temporal lobes in the T2-weighted MR image decreased, and the patient's cognitive function [global deterioration scale (GDS) 4 points, mini-mental state examination (MMSE) 25 point] also improved (GDS 1 points, MMSE 29 points). PCV chemotherapy can therefore be an alternative therapeutic option for patients with GC who cannot be treated with radiation therapy or other chemotherapies.