For the early detection of lung cancer at a stage when it is localized and hence resectable, persons in a high-risk group should be screened periodically with sputum cytologic studies and chest radiographs. For determination of the intrathoracic extent of a lesion, posteroanterior and lateral chest radiographs should be followed by computerized tomography to evaluate the hila, mediastinum, pleura, and chest wall. Computerized tomographic examination of the chest should be extended to include the upper abdomen. The adrenal glands can be evaluated by such examination, but adequate examination of the liver requires both precontrast and postcontrast computerized tomography scans. The radiologic workup for assessing distant metastases to the liver, brain, or bone should be performed only when clinical and biochemical findings suggest such metastases. For detection of recurrent carcinoma following treatment, computerized tomograms of the chest are more sensitive than routine radiographs. Magnetic resonance imaging may prove useful in the future for initial staging and for differentiating posttreatment fibrosis from recurrent bronchogenic carcinoma.