Studies have shown that nitric oxide (NO)-induced apoptosis is mediated by a variety of cellular signaling pathways. However, the information is relatively limited to neural progenitor cells (NPCs). In this study, the role of p53 in the NO-induced apoptosis was examined in an in vitro model of NPCs. Comparisons were made between NPCs derived from either wild type or p53 knockout mice brain stimulated by diethylenetriamine/nitric oxide adduct (DETA/NO), an established NO donor that constantly releases NO through its known first order pharmacological kinetics and prolonged half-life. We found that treatment by DETA/NO both time- and dose-dependently induced a significant increase of apoptosis in wild type NPCs, while p53 knockout NPCs were resistant to the DETA/NO challenge. In addition, the DETA/NO-triggered alteration of mitochondrial membrane permeability, cleavage of caspase-9/3, and expression of pro-apoptotic Bcl-2 family members noxa and puma occurred in wild type NPCs but not in p53 knockout NPCs. Our current results suggest a central role of p53 in the NO-induced apoptotic pathway in NPCs, which may hence provide new insights into the regulation of cell death in NPCs that respond to overproduction of NO in injured brain.