Despite medical advances lung cancer remains the leading cause of cancer deaths. Lung cancer is usually recognized late in its natural history and at presentation in 80 % unresectable. Smoking history is the most important risk factor. At present time, screening for lung cancer is not recommended. The only chance for cure is tumour resection in early stages, performed in about 20 % of all lung cancer cases. Histological subtypes are non-small cell lung cancer (NSCLC) (80 % of lung cancers) and 20 % small cell lung cancer (SCLC). TNM-staging has important influence on prognosis and therapy. After identification the tumour should be staged using the TNM system. Currently diagnosis and staging rely predominantly on chest radiography and computed tomography (CT) scanning. Positron emission tomography (PET) identifies the tumour by its metabolic activity and helps to find malignant nodal or systemic lesions. Flexible bronchoscopy is the key investigation in the diagnosis and staging of patients with suspected lung cancer. Endobronchial ultrasound guided transbronchial fine needle aspiration (TBNA) may be utilized to improve the bronchoscopic results in mediastinal staging. Internistic thoracoscopy or video assisted thoracoscopic surgery (VATS) may be used in malignant pleural effusions. Mediastinoscopy staging is the gold-standard for mediastinal staging.