Despite advances in the treatment of cancer, the prognosis of patient diagnosed with metastatis cancer to the brain remains poor. The role of neural stem cells as a viable tool in the treatment of metastatic cancer to the brain alone or in conjuction with current therapeutic modalities is promising. Both murine and human neural stem cells (NSCs) have been shown to migrate through the central nervous system (CNS) and infiltrate tumors and other pathological disease states of the brain. Genetic modification of NSCs to produce cytotoxic or immunomodulatory agents in the vicinity of a primary tumor and/or satellite lesion or has proven instrumental to the reduction of tumor bulk in murine models. Although the use of stem cells proves to be a volatile social topic, scientists have discovered that NSCs are present in the adult brain and continue to propagate and differentiate. These cells may be isolated and cultured to produce clonal NSC lines that are capable of self renewal and differentiation when introduced into the CNS. In this chapter, we describe protocols currently used in ourlab for the successful maintenance of NSCs in vitro advancing the role of neural stem cells in the treatment of brain tumors.