When comparing the test parameters of oxidative stress within one genotype of the AGT gene, the most significant increase in H2O2, О2•- and 8-isoprostane (compared with controls) was found in patients with COPD + hypertension and the M/M genotype of the AGT gene, which was also due to lower control values of test parameters in subjects with the M/M genotype compared with M/T. This evidence concerns the gene AGT and chronic obstructive pulmonary disease.