Neural stem cells are defined as cells that either gives rise to or derives from the cells of the central nervous system and have the unique properties of stem cells, i.e. self-renewal and multipotentiality. One of the widely used methods of expanding neural stem cells under culture conditions is based on the capacity of these cells to divide continuously when cultured in serum-free medium supplemented with various growth factors. One common method used is to grow neural stem cells as free-floating aggregates of cells called neurospheres. Neurospheres can be generated from several structures of the embryonic and adult mammalian brain. Although viable lines can be generated from crude extracts of brain, a precise dissection is crucial to get a pure population of cells. Here we describe methods for dissection, isolation and generation of neurospheres from embryonic ganglionic eminences and adult subventricular zone of mice and rats.