Lung cancer is one of the most lethal cancers and has a high incidence as well as high mortality. Smoking (both active and passive) is the single most important risk factor in the causation of lung cancer. Bronchogenic carcinomas arise from the bronchial epithelium or mucus glands and are classified into: (i) non-small cell lung cancer (NSCLC): squamous cell carcinoma, adenocarcinoma (including bronchioloalveolar), large cell carcinoma, (ii) small cell lung cancer (SCLC). The signs and symptoms are either related to the primary tumour, locoregional spread, distant metastases, or paraneoplastic syndromes. Evaluation of patients with lung cancer consists of diagnosing the primary tumour and typing it as NSCLC or SCLC. NSCLC is staged as standard stages 1-IV. SCLC is staged into limited stage disease and extensive stage disease. Both staging are based on the tumour, node and metastasis classification. Performance status is done by the Eastern Co-operative Oncology Group staging. Treatment consists of surgery, chemotherapy, radiotherapy or a combination of these. In addition the chapter discusses role of screening in lung cancer, approach to malignant pleural effusion with unknown primary, approach to a solitary pulmonary nodule, lung cancer prevention and future directions.