Astroblastoma is a rare and controversial tumor about which little is known. We have made the diagnosis in seven patients since 1990 at Memorial Sloan-Kettering Cancer Center. Four patients had astroblastomas with anaplastic features, whereas three patients had tumors which were well-differentiated. All three patients with low grade lesions are alive and recurrence free after surgery alone (mean follow-up 29 months). All four patients with anaplastic astroblastoma were treated with surgery, radiotherapy and chemotherapy. One died of infection during induction chemotherapy. Two others died of tumor progression at 28 and 42 months. Radiographic response to chemotherapy was seen in one patient. The results of our series and other reports suggest that anaplastic histology is a prognostic factor in the setting of astroblastoma. More aggressive treatment is necessary for patients with anaplastic astroblastoma although the precise role of irradiation and chemotherapy cannot be defined at this time.