Neural progenitor cells (NPCs) are characterized as undifferentiated cells with the ability of self-renewal and multipotency to give rise to other cells of the nervous system. In our in vitro study we demonstrate the proliferative and differentiative potential of NPCs isolated from the spinal cord at different developmental stages (embryonal, early postnatal, adult), maintained and expanded within neurospheres (NSs). Using the NSs culture system, we examined the size, number of NSs and their fate when exposed to differentiation conditions. Based on immunocytochemical analyses for cell markers (MAP 2, GFAP, RIP) we evaluated the occurrence of various cell types: neurons, astrocytes and oligodendrocytes. The results show that NSs increased in size during cultivation time via NPC proliferation, but proliferation potential decreased Turing maturation stages. In addition, NPCs derived from spinal cord developmentally different stages gave rise to a consistent ratio of glial and neuronal progeny (3:1), and adult tissues represent a comparable source of NPCs compared to embryonal and early postnatal tissues. These data provide useful information for large-scale in vitro expansion of NPCs required for potential cell therapy after spinal cord injury.