Malignant gliomas are a heterogeneous group of tumors that are associated with significant morbidity and mortality. The development of the malignant phenotype is the result of a complex series of events that influence gene expression, angiogenesis, and invasion and favor the growth of tumor cells. Currently, the management of malignant glioma consists of symptom control and cytoreduction with a combination of surgery, radiation therapy, and chemotherapy. However, there is no satisfactory regimen available for adjuvant or salvage chemotherapy for these neoplasms. An overview of the biologic mechanisms, grading systems, and treatment options for anaplastic astrocytoma and glioblastoma multiforme is presented.