Background. The structural changes in the airways of asthmatics are also referred to as remodeling and can be identified using high-resolution computerized tomography (HRCT). Objectives: To find out whether there are any abnormal HRCT features which can be attributed to asthma and their clinical correlates, and any differences of abnormal HRCT features between asthmatics and patients with chronic obstructive pulmonary disease (COPD). Methods: We performed (HRCT) scans to assess airway remodeling in 160 nonsmoker asthmatics compared with 27 patients with COPD. Results: Bronchial wall thickening, hyperlucency, centrilobular prominence, bronchiectasis, thick linear opacities and mucoid impaction were all correlated with disease severity in asthma. FEV1 values were inversely correlated with bronchial wall thickening, hyperlucency, mucoid impaction, linear shadows, centrilobular prominence and bronchiectasis. In adddition, thick linear opacities, mucoid impaction and bronchiectasis were more prominent in those patients with a long duration of asthma. Bronchial wall thickening, thick linear opacities, mucoid impaction, bronchiectasis and emphysema were more prominent in COPD patients compared with asthmatics. There was no difference with regard to age, mean values of FEV1 and the duration of asthma between allergic and nonallergic asthmatics as well as abnormal HRCT findings. Conclusions: COPD patients have more prominent HRCT findings as compared with asthmatics. In the asthmatics, abnormal HRCT findings are more prominent with increased severity, decreased FEV1 values and the duration of asthma. The remodelling of airways in allergic asthmatics did not differ from that in their nonallergic counterparts as determined by HRCT. Copyright (C) 2002 S Karger AG, Basel.