Objective:To study the mode of cell death ocurring in the delayed neuronal death after rat transient global ischemia. Methods:TUNEL method was used to morphologically detect the injured nerve cells, immunohistochemistry staining to detect Bax and in situ hybridization to detect bcl-2 mRNA. Results:The results were as follows: TUNEL-positive neurons were stained in hippocampuses of operated rats ,which was mostly located in CA1 zone, increased as time passed, reached max after day 3. Apoptotic bodies and the neurons forming the apoptotic bodies were also found. Bcl-2 mRNA positive signals were widespread in CA3 pyramidal neurons. On the contrary,Bax-positive neurons was mostly located in the CA1 subfield.These 2 signals occurred on reperfusion 8 h,reached max on 24 h and markedly reduced on 72 h.Conclusion:The findings strongly suggest :(1)Apoptosis may contribute to the delayed neuronal death .(2) Selected expression of different members of bcl-2 gene family may play an important role in determining the relative sensitivity of neuronal subpopulations to ischemia.