Recent studies show that activation of transcriptional factors NF-E2 related factor 2 (Nrf2) is a key initiation step in the cellular response against chemical stress and Nrf2 involves in the regulation of expression of gamma-glutamylcysteine synthetase heavy (GCSh) and light subunit (GCS1). To our knowledge, however, there is no study reported whether disruptions in Nrf2 and GCS occur in oxidative stress induced by Deltamethrin (DM). Wistar male rats were administrated (daily dose is respectively 0,3.1, 12.50 mg/Kg BWT) with i.p, for five days. The relative amount of mRNA expression of genes was measured by RT-PCR. The protein level was immunohistochemistry detected. There was no effect on mRNA expression level of GCSh and Nrf2 gene in both cerebral cortex and hippocampus tissue in rats administrated with DM. However, the mRNA level of GCSl gene in cerebral cortex of high dose group as well as in both cerebral cortex and hippocampus of low dose group was significantly lower than that in corresponding tissue of control group, decreased to 71.1 %, 63.6%, and 75.2% of mRNA level of corresponding tissue of control group (P<0.001). There was no obvious effect on protein level of both GCSh and Nrf2 in hippocampus as well as on that in cerebral cortex in rat treated with DM.