['Pathogenesis of chronic obstructive lung disease (COPD) includes primary inflammatory events, multiple vascular reactions, remodeling of bronchial and vascular walls.', 'The aim of present single-center study was to assess relations between angiotensin-converting enzyme (ACE) gene and prevalence of clinical symptoms characteristic to COPD.', 'The study involved sixty-three male patients with COPD (44-86 years old, a mean of 60.4 years). COPD diagnostics was performed according to common criteria, including evaluation of systolic pressure in pulmonary artery (SPPA) and endothelial disfunction (ED). Genotyping of ACE I/D was performed by means of gene-specific PCR.', '1. Allele distribution of studied gene alleles among COPD patients did not differ from control age-matched group. 2. Detectable endothelial dysfunction in COPD patients was shown to correlate with high-producer D allele of ACE gene, at an odds ratio of 6.632 (CI\xa0=\xa01.67-26.31; chi2\xa0=\xa08.39, p\xa0=\xa00.004). Moreover, detectable ED correlated with numbers of COPD exacerbations per year.'] Is common intronic D variant of ACE gene associated with endothelial dysfunction in COPD?