Individual susceptibility to different environmental agents is expected to be associated with alterations in metabolism of xenobiotics. Thus, genetic polymorphism of glutathione S-transferase (GST) can be recognized as a potential risk modifier in lung cancer development. The distribution of GSTM1 and GSTP1 genotypes was studied in a group of 138 diagnosed lung cancer patients and in 165 controls living in central Poland and RFLP-PCR technique was applied. The frequency of GSTM1 null genotype and GSTP1 Val single and duplicated alleles was similar among patients and controls. GSTM1 homozygous deletion was most prevalent in small-cell carcinoma groups (adjusted odds ratio (OR): 2.32, 95% confidence interval (CI): 0.98-5.52). In patients and controls, GSTM1A genotype was most frequent (34.1% vs. 37.0%). The estimated lung cancer risk for GSTM1 null, GSTP1 Ile/Val and GSTP1 Val/Val combined genotype was 1.44 (95% CI: 0.73-2.83), suggesting the absence of modifying effect of defective GSTM1 and GSTP1 alleles on lung cancer predisposition.