There were studied distribution of polymorphic variants of gene of repair of DNA XPD A751C in lung cancer depending on histological type of tumor (small cell / non-small cell lung cancer) and the prevalence of tumor process (with foci / without foci of metastasis). It was found a significant increase in the incidence of minor allele C, CC and AC genotypes of the polymorphic site of gene XPD A751C in patients with lung cancer. We estimated relative risks of lung cancer development in carriers of polymorphic variants of gene XPD A751C. The heterozygous genotype AC polymorphism of gene XPD A751C is characterized by the greatest risk of developing lung cancer with small cell histological type. Homozygous CC genotype of the polymorphic site of gene XPD A751C is associated with non-small cell lung cancer development. Statistically significant differences in the distribution of polymorphic variants of gene A751C XPD depending on spread of cancer were not received.