Topotecan is a chemotherapeutic agent that is active in the treatment of small cell lung cancer (SCLC). As a first-line agent in chemotherapy-naive patients with extensive disease SCLC, topotecan has a 39% response rate. As a second-line drug in SCLC patients with "sensitive" disease and "refractory" disease, the response rate is greater than 38% and less than 10%, respectively. The combination of topotecan and paclitaxel exhibits a promising overall response rate of 92% in chemotherapy-naive patients with extensive disease SCLC. Further studies are warranted with topotecan used in combination with other agents, including radiation therapy in patients with SCLC.