Most of chemical carcinogens are metabolized and activated in vivo by phase I enzymes including the microsomal cytochromes P450 (CYP) and epoxide hydroxylases. The carcinogens and their metabolites are detoxified by the phase II enzymes that include various transferases such as glutathion-S-transferases (GST). Some studies have demonstrated the association of the polymorphisms in CYP2E1 genes with the susceptibility to lung cancer. Subsequently, the polymorphisms appear to be important biomarkers that provide information for assessments of exposure and total burden of environmental carcinogens. Therefore, the investigation of the polymorphisms in these genes will provide information not only for the prediction of individual cancer risks but also for the prevention of cancer. In this review, we will summarize the polymorphisms in the CYP2E1 genes and their relationship to the lung cancer susceptibility and prognosis. Gene polymorphisms such as CYP2E1 will contribute to the evidence based prevention (EBP).