Objectives: To observe the roles of nuclear factor κB(NF κB) in corticosterone injured hippocampal neurons. Methods:Two groups of primary hippocampal neurons were cultured for 8~10 days. One group was treated with 1×10 -5 mol/L corticosterone. The total cellular nuclear protein levels were extracted at 0.5,1,2 and 4 hours, respectively. Electrophoresis mobility shift assay (EMSA) was used to detect the expression of NF κB activation. Another group was treated with κB decoy DNA(25 μmol/L) to inhibit the activity of NF κB for 2 hours before 1×10 -5 mol/L corticosterone was intervened. MTT was used to observe the effects of corticosterone induced neurons injury after 6,12,24 and 48 hours. Results:The activity of NF κB became significantly lower than that in the control group after corticosterone acted on neurons for 1 hour. As time went on, its effects became more conspicuously. The injury of hippocampal neurons aggravated when the activity of NF κB was inhibited by κB decoy DNA. Conclusions: NF κB plays a protective role in corticosterone induced hippocampal neuron injury.