Transcription factor Nrf2 regulates the basal and inducible expression of detoxifying and antioxidant genes. Recent studies using nrf2-null mice suggest that Nrf2 dysfunction might be involved in the pathogenesis of human diseases. To gain insight into the relationship between impairment in the NRF2 gene and human diseases, we attempted to identify polymorphisms in the human NRF2 gene. We determined the structure of the NRF2 gene and found three single nucleotide polymorphisms and one triplet repeat polymorphism in its regulatory region. These results provide a molecular basis for the genetic analysis of the NRF2 gene. The frequency of each polymorphism was examined in two groups of patients with systemic lupus erythematosus and chronic obstructive pulmonary disease. This study did not reveal a close connection between the risk of these diseases and the polymorphisms. However, available lines of evidence suggest the importance of examining the link between NRF2 polymorphisms and other oxidative stress-related diseases.