Glioblastoma multiforme (GBM), the most aggressive form of primary brain tumors, contain small population of tumor cells that carry cancer stem cell properties. These brain tumor stem cells (BTSCs) are highly invasive and mobile, have the capacity to self-renew, and are more resistant to radiation and chemotherapy. BTSCs can migrate away from the primary tumor sites and form microsatellite tumors. Thus, BTSCs have been proposed to play a key role in tumor progression, metastasis, and recurrence. Recent studies indicate that neural stem cells have the innate ability to track down tumor cells and may even slow tumor growth and progression. Thus, therapeutic neural stem cells can be developed by “arming” normal neural stem cells with genes cytotoxic to glioma cells and, more importantly, to BTSCs. Studies are currently underway to explore this new therapeutic approach to treat GBM using neural stem cells.