CYP1A1 is a gene involved in the high aryl hydrocarbon hydroxylase -inducible phenotype, which is a genetically-determined variation among individuals that has been associated with lung cancer risk. More specifically, CYP1A1*2B and *4 polymorphisms have been associated with high susceptibility to lung cancer among cigarette smokers. DNA was obtained from blood samples and we studied by PCR-RFLP the distribution of CYP1A1*2B (n=248) and *4 (n=222) polymorphisms in healthy controls and 222 lung cancer patients from a Mexican population. Comparisons between groups showed an increased risk for lung cancer patients of *2B/*2B (18%; OR 7.6; 95% CI 3.0-19.2) and *4/*4 genotypes (15%; OR 11.45; 95% CI 2.19-59.85) compared to the control group (1% for *2B/*2B and 4.4% for *4/*4). A significant association between lung cancer and homozygous *2B/*2B passive smokers and *4/*4 ever (cigarettes) and passive smokers was also observed (p