Assessment of exhaled breath condensate (EBC) pH is a promising method for investigating and monitoring airway pathology in a number of lung diseases. In this cross-sectional study we tested whether development of lung cancer is associated with acidification of EBC. EBC was collected in 43 smoking patients with lung cancer (squamous cell carcinoma: 17 patients, adenocarcinoma: 16 patients, and small cell lung cancer: 10 patients) before receiving any anticancer treatment and in 20 healthy smokers without any clinical and radiological evidence of pulmonary tumor. EBC pH was measured by CO 2 gas standardization, the most reliable and accurate method at present. EBC pH in patients with pulmonary tumor (6.68±0.02) and in controls (6.63±0.05) was similar (p>0.05). Results were affected neither by the histological subtype nor the stage of the tumors. Our data suggest that assessment of EBC pH is of limited value for the diagnosis and/or screening of lung cancer.