Lung cancer is a common malignancy and remains the leading cause of cancer-related deaths in both men and women in the United States. Imaging plays an important role in the detection, diagnosis, and staging of the disease as well as in assessing response to therapy and monitoring for tumor recurrence after treatment. This article reviews the staging of the two major histologic categories of lung cancer—non–small-cell lung carcinoma (NSCLC) and small-cell lung carcinoma—and emphasizes the appropriate use of CT, MRI, and positron emission tomography imaging in patient management. Also discussed are proposed revisions of the International Association for the Study of Lung Cancer's terms used to describe the extent of NSCLC in terms of the primary tumor, lymph nodes, and metastases descriptors.