Advances in the treatment of limited small-cell lung cancer (L-SCLC) have led to improved short-term outcome. However, it is not clear how well this predicts the ultimate fate of the patients. This may be affected by late relapse of SCLC, the development of second malignancies, and the long-term toxicity of therapy. To address this issue we report follow-up in excess of 5 years on a cohort of 36 patients who had high short-term survival resulting from treatment with chemotherapy combined with cranial and thoracic irradiation. All patients were followed until death or the time of analysis. The initially promising result of 31% survival at 3 years, was reflected in survival from SCLC of 27% at 5 years, and 23% at 9 years. However, when death from all causes was analyzed, survival was only 19% at 5 years and 7% at 9 years. There were 2 survivors disease-free at 7 and 8 years; 7 patients died of other causes without any evidence of SCLC. Among those not dying of SCLC, 4 patients developed second malignancies with a risk of 22% at 3.2 years and 50% at 8 years. Clinical neurotoxicity developed in 3 patients. These data suggest that cure of SCLC is possible in a modest proportion of patients with limited disease, but that the survivors are at significant risk of developing second malignancies which emerge as the most common cause of death during prolonged follow-up. Successful outcome of treatment is further hampered by the occurrence of neurotoxicity. Clinical strategies to prevent these sequelae of therapy are discussed.