SUMMARY Objective The relationship between chronic rhinosinusitis, asthma and allergic rhinitis is well known, but only recently has the scientific community started to evaluate these as different manifestations of a common pathogenic phenomenon, considering them as a unified airway disease. Methods Twenty-two patients with chronic rhinosinusitis treated with endoscopic sinus surgery (ESS) were included in the study. Sino-nasal assessment questionnaire (SNAQ) investigating subjective evaluation of sino-nasal state was administered to patients, while objective evaluations included nasal endoscopy, sinonasal CT, skin prick tests, nasal cytology, spirometry, bronchodilator responsiveness testing and sputum eosinophil count. All tests were performed before surgery. Two months after surgery, SNAQ questionnaire, nasal endoscopy, spirometry and bronchodilator responsiveness testing were repeated. Results All patients had significant improvement of subjective status: mean SNAQ score decreased in all from 99.31 to 16.04. Mean Forced Expiratory Volume in the 1 st second (FEV 1 ) significantly improved after surgery from 3.23 to 3.45 L/s. Conclusions ESS achieved a beneficial effect on upper and lower airway status in patients with chronic rhinosinusitis with or without lower airway diseases.