The non-invasive character of exhaled breath (EBC) collection makes this fluid attractive for monitoring the respiratory tract by the measurement of various compounds. Because EBC is likely to reflect the composition of the airway-lining fluid, it can provide valuable information on possible disease states. Aim of our study was to apply proteomic technology to the study of EBC samples collected from single patients with pulmonary emphysema associated to alpha(1)-antitrypsin deficiency. The protein profiles from EBC of twenty patients and of twenty-five healthy individuals, used as controls, have been analyzed in parallel by a combination of 1-DE, 2-DE, micro-HPLC and MS. These sensitive techniques allowed to identify a number of cytokines and cytokeratins. Their level was found to be higher in patients than in controls.