Ataxia-telangiectasia (A-T) is a progressive degenerative disorder that results in major neurological disability. In A-T patients, necropsy has revealed atrophy of all cerebellar cortical layers with extensive Purkinje and granular cell loss. We have previously identified an increase in phospho-p38MAPK levels, which was accompanied by downregulation of Bmi-1 and upregulation of p21, as key components of the mechanism causing defective proliferation of neural stem cells (NSCs) isolated from subventricular zone (SVZ) of Atm-null mice. Our results demonstrate that restoration of NSCs by pharmacologic inhibition of p38MAPK signaling has the potential to treat neurological defects of A-T. This study provides new insights into the therapeutic strategy targeting NSCs rather than replacing impaired neurons not only for A-T, but for other neurodegenerative disorders as well.