Our study is the first to examine serum MMP-9, TIMP-1 and the MMP-9/TIMP-1 ratio for their predictive value for the presence of COPD and to assess the relationship with the full range of functional lung parameters obtained by spirometry, single breath diffusion capacity for CO, body plethysmography and clinical COPD indicators. This evidence concerns the gene MMP9 and chronic obstructive pulmonary disease.