Objective To investigate whether type-1 and type-2 astrocytes (T1A, T2A) express the characteristic molecules of neural stem cells. Methods Purified cultures of cortical O-2A progenitor cells, T1A and T2A were prepared from neonatal rats. The expression of nestin and stage specific embryonic antigens1 (SSEA-1) were detected by immunocytochemistry labeling. O-2A progenitor cells, TIA and T2A were cultured in the presence of basic fibroblast growth factor (bFGF) and epidermal growth factor (EGF) for 10 days. Then the morphological changes of the above cells were examined. Results Expression of nestin was observed in O-2A progenitor cells and T2A, while T1A was negative for nestin immunostaining. Expression of SSEA-1 was only detected in T2A. After treated with bFGF and EGF, T2A changed into neurosphereslike morphology and could be passaged continuously. The spheres were also positive for nestin immunolabeling. After plated onto PLLcoated substrates for 10 days, cells with typical morphologies of neuron, astrocytes and oligodendrocytes were observed to migrate from the spheres. Conclusion Nestin and SSEA-1 were expressed differently in T1A and T2A. T2A induced by extracellular signals may acquire some properties of the multipotent neura