An analysis of the long-term results of treatment of 3,681 patients with small cell lung cancer (SCLC) is presented. The data were obtained from major centres in the UK who were conducting treatment trials during the period 1978-1986 and for whom complete computer records and follow-up were available. A total of 217 (5.9%) survived 2 years or more. Two year survival for patients presenting with limited disease (LD) was 8.5% and for extensive disease (ED) 2.2%. Death from SCLC continued until 7 years after diagnosis but not thereafter. At this point overall survival was 3% (3.6% LD, 1.1% ED). Survival after 2 years was not affected by initial disease extent, sex, thoracic radiotherapy or prophylactic cranial irradiation. Death from causes other than SCLC continued throughout the period of observation. Vascular disease, respiratory failure and second tumours were the main other causes of death. The better survival in younger patients was mainly attributable to few deaths from these other causes. These results indicate that only a small proportion of patients with SCLC are cured by current treatment. Although shorter term improvement in survival has been obtained with current treatment, the poor overall long-term results support studies exploring new approaches to cure and to palliation.