The number of lung cancer-related deaths has increased since the 1960 and has become the leading cause of cancer-related death in Japan. It is anticipated that the number will double in the next 20 years. Chemotherapy is a hopeful systemic therapy because of distant metastases due to lung cancer. Platinum based doublets remain the standard of care for the first-line treatment of metastatic NSCLC. As salvage chemotherapy for patients, the effectiveness of docetaxel has been confirmed. The standard chemotherapy for extensive SCLC is the combination of cisplatin and irinotecan or etoposide. Recently, randomized trials have shown that platinum-based chemotherapy has the potential to improve survival among patients with completely resected NSCLC. Recent advances in molecular biology and genetics have created new molecular targeted therapies for lung cancer. New anti-cancer agents, including gefitinib, erlotinib, bevacizumab, pemetrexed and amrubicin, are being developed currently.