We aimed to investigate a potential effect of genetic polymorphisms in genes XRCC1 (Arg399Gln), OGG1 (Ser326Cys), XRCC3 (Thr241Met), and XRCC4 (Ile401Thr) on the level of DNA damage and repair in COPD patients and controls. This evidence concerns the gene XRCC4 and chronic obstructive pulmonary disease.