Cytochrome P-450 CYP2C9 enzyme is involved in the metabolism of xenobiotics and carcinogens. Variant alleles CYP2C9*2 and CYP2C9*3 encode enzymes with altered properties, and CYP2C9*2 has been related to lung cancer risk. The frequency of CYP2C9 variant alleles was analyzed in genomic DNA from 104 patients with lung cancer and in 197 healthy controls. No statistically significant differences in CYP2C9 genotypes, allele frequencies or predicted phenotypes were observed between overall patients and controls. Unconditional logistic regression for the interaction smoking/genotype indicate P values of 0.66 and 0.62 for carriers of CYP2C9*2 and CYP2C9*3, respectively, versus individuals without these mutations. The P values for the same interaction in carriers of one and two mutated genes were 0.56 and 0.67, respectively, versus individuals homozygous for non-mutated genes. Independent analyses of histological types of lung cancer also indicated the absence of statistically significant differences as compared to healthy subjects. Association between CYP2C9 polymorphism and lung cancer risk was not identified in this study.