Objective To research the effects of olfactory ensheathing cells (OECs) on the proliferation of neural stem cells (NSCs). Methods OECs and NSCs were separated and cultured in vitro. The proliferation of NSCs was observed by means of co-culture and twochamber shared medium culture with OECs. For investigating the mechanism of the proliferation of NSCs, the cytokines and their receptors of OECs were tested by immunocytochemistry and RT-PCR.Results After 4 days in co-culture and twochamber shared medium culture, the population of NSCs were increased significantly (P<0.05), and some of them were differentiated. The result of RT-PCR showed that OECs could express mRNA of β-NGF, BDNF, NT-3, PDGFB, trkA and trkB, but not NT-4 Moreover, positive staining of NGF, BDNF and p75 was observed in the cytoplasm of OECs by immunocytochemistry. Conclusions OECs can express or secrete a l