The necessity for a compulsive attitude toward preoperative assessment of lung cancer is to be emphasized, since rational treatment and prognosis depend largely on the stage of disease at the time of diagnosis. In the preoperative setting, the techniques used should be sequential, logical, and help to identify patients suitable for treatment with curative intent. With regard to the primary tumor (T status), the accuracy of CT or MRI to predict the need for extended resections is limited. Similarly, all noninvasive methods to determine the nodal status (N) are valuable, but mediastinoscopy has a greater sensitivity and specificity than either CT or MRI. The role of routine organ screening for the detection of distant occult metastasis in the asymptomatic patient is still controversial. Ultimately, the prognosis of the resected patient with lung cancer is based on complete intraoperative staging, which can be done by either systematic node sampling or complete lymphadenectomy. At present, neither of these techniques has been shown to improve the quality of staging or survival.