We describe the in vitro isolation and expansion of cells capable of forming neurosphere-like aggregates from human adult bone marrow. Cells within these passaged spheroids can differentiate into astrocytes, specific neuronal subtypes, and oligodendrocytes and have gene expression profiles similar to human fetal brain-derived neural stem cells. Genetically modified neural-competent bone marrow-derived cells efficiently migrate toward distant sites of brain injury and tumor in vivo, where they differentiate and express therapeutic transgenes when transplanted into the brains of mice. These studies suggest that adult bone marrow may serve as a large reservoir for autologous neural stem-like cells for future therapeutic strategies.