In carcinomas of the lung, the treatment design and the prognosis are dependent on the histological type and anatomical spread of the tumor and also on the general condition of the patient. Evaluation of these parameters requires an extensive clinical staging program that is nonetheless slanted to the individual subjective status of each patient. We generally distinguish a standardized basic diagnostic procedure (patients’ history, physical examination, serum biochemistry, blood counts, chest X-ray with chest CT and radioscopy, bronchoscopy) from a specialized, more detailed individual diagnostic procedure (perfusion scintigraphy of the lung, nuclear magnetic resonance tomography, mediastinoscopy, pleuroscopy, diagnostic thoracot-omy, procedures for the exclusion of distant metastases). The pre therapeutic diagnostic assessment also includes evaluating the risk of therapy for each individual patient, especially in the case of surgical intervention. Posttherapeutic complications should not cause great problems if the risk factors have been carefully evaluated before treatment. In the interest of the patient, it must be stipulated that this cost-effective and efficient investigation program is rapidly implemented, since unclear and doubtful findings may entail a greater burden for the patient than the definitive diagnosis of a tumor.