Objective To observe the effects of transient hypoxia in the brain on the expression level of neurogenic differentiation factor (NeuroD). Methods The model was established as previously described by Grojean. Briefly, newborn rats were transiently exposed to 100% NSUB>2/SUB>.Thirty-three rats were randomly divided into the normal control group, 10min hypoxia group and 20min hypoxia group. The expression level of NeuroD in a rat brain was determined with Western blotting and immunofluorescence staining. Results Immunofluorescence analysis showed that NeuroD was expressed in the cerebral cortex and dentate gyrus. Western blotting analysis demonstrated a significant upregulation in the NeuroD expression with the time after hypoxia. The expression of NeuroD significantly increased in the 10min hypoxia group compared to the control group ( EM>P/EM> <0.01), with the highest expression level being seen in the 20min hypoxia group (compared to 10min hypoxia, EM> P/EM> <0.01). BR> Conclusion Transient hypoxia induces the up-regulation of NeuroD, which was found to express mainly in neural stem /progenitor cells rich areas, i