Advances in technology have increased the contribution of radiology in understanding and evaluating diseases of the airways. In patients with hemoptysis, CT is now established as a complementary technique to bronchoscopy, or as an alternative to bronchoscopy in selected cases. The introduction of high-resolution CT has improved the detection and assessment of bronchiectasis and small airways disease, allowed better correlation between pathologic changes and radiologic appearances, and provided new insights into possible links between small airways disease and bronchial disease.