High-resolution computed tomography (HRCT) is the imaging modality of choice to evaluate most bronchial tree lesions, especially those affecting small airways. It can confirm the diagnosis of bronchiectasis with high sensitivity and specificity and may contribute to the investigation of bronchiolitis (particularly diffuse panbronchiolitis and bronchiolitis obliterans) and other inflammatory disorders of the airways. HRCT can also reliably detect obstructing bronchial lesions such as tumors or broncholithiasis. It may also provide useful clues to the diagnosis of bronchial fistula, dehiscence, or rupture as well as permit the study of many pulmonary congenital abnormalities. This article describes the CT techniques recommended in each clinical situation and reviews the HRCT findings in diseases of the airway.