High-resolution computed tomography (HRCT) provides detailed information regarding the lung parenchyma and can delineate structures down to the level of the secondary pulmonary lobule. This information allows for an accurate morphologic analysis of the pathologic processes affecting the lung. As a result, HRCT has become an important tool in the evaluation of interstitial lung disease and plays a significant role in early detection, characterization, and diagnosis of these disorders. In this article, the components of an HRCT examination are defined. HRCT features of interstitial lung disease are illustrated including reticulation, honeycombing, traction bronchiectasis, architectural distortion, nodules, ground-glass opacities, mosaic attenuation, and cystic spaces. HRCT patterns of interstitial lung disease are discussed including those seen in specific entities such as usual interstitial pneumonia, collagen-vascular disorders, chronic eosinophilic pneumonia, respiratory bronchiolitis-associated interstitial lung disease, pulmonary Langerhans cell histiocytosis, lymphangioleiomyomatosis, hypersensitivity pneumonitis, and sarcoidosis. Specific applications of HRCT in the evaluation and management of interstitial lung disease due to drug-induced pulmonary toxicity and occupational lung disease are reviewed and the role of HRCT in quantifying and monitoring disease extent is discussed. Finally, the diagnostic accuracy of HRCT is examined relative to conventional radiographs and standard CT in the evaluation of interstitial lung disease.