Murine embryonic day 14 or E14 neural stem cells (NSCs), first isolated and characterized as a stem cell in culture, are a unique population of cells capable of self-renewal. In addition, they produce a large number of progeny capable of differentiating into the three primary phenotypes-neurons, astrocytes, and oligodendrocytes-found in the adult mammalian central nervous system (CNS). A defined serum-free medium supplemented with epidermal growth factor (EGF) is used to maintain the NSCs in an undifferentiated state in the form of clusters of cells, called neurospheres, for several culture passages. When EGF is removed and serum added to the medium, the intact or dissociated neurospheres differentiate into the three primary CNS phenotypes. This chapter outlines the simple NSC culture methodology and provides some of the more important details of the assay to achieve reproducible cultures.