Thin-section or high-resolution computed tomography (HRCT) is used in children for the investigation of disorders such as airway disease and diffuse interstitial lung disease. Advances in CT technology have resulted in faster scan acquisition times, enabling images of sufficient diagnostic quality to be obtained in children during gentle respiration. Whilst radiation dose is an important consideration, the dose of a thin- section CT is approximately one-seventh that of a conventional CT examination. As in adults, thin-section CT is more sensitive than chest radiography and may demonstrate abnormalities despite a normal chest radiograph. HRCT is also more specific than chest radiography for categorizing airway, airspace or interstitial processes in children. The current review will concentrate on the value of CT in airway diseases and diffuse interstitial lung disease.