This study investigated the proliferation and differentiation of adult neural progenitor cells (aNPCs) derived from the striatum and substantianigra (SN) of parkinsonian rats. We found that aNPCs isolated from the two areas of parkinsonian rats readily formed nestin-enrichedneurospheres in vitro and exhibited an ability to differentiate into either neurons or astrocytes. Injection of epidermal growth factor (EGF)and basic fibroblast growth factor (bFGF) into the striatum of parkinsonian rats prior to the harvesting striatal aNPCs significantly increasedthe neurosphere formation rate and multiple differentiation capacity of these aNPCs when cultured in vitro. These data suggest that striataland nigral adult NPCs in parkinsonian rats retain the abilities of proliferation and differentiation in vitro. In addition, exogenously appliedgrowth factors could up-regulate the developmental potential of aNPCs. We conclude that our data supports the notion that endogenous cellreplacement therapies may be useful for the future treatment of Parkinson’s disease (PD).