Clinical and laboratory parameters can predict response to chemotherapy and long term survival in small cell lung cancer, and may predict those at risk of early treatment related toxicity. This paper reviews the predictive models that have been developed to divide patients into prognostic groups for response and survival on the basis of clinical and laboratory parameters. These factors may be used for the stratification of patients in clinical trials and to help clinicians make appropriate treatment decisions for individual patients. A number of treatment-related factors can also affect outcomes. The evidence for interventions to prevent treatment deaths in high risk patients, such as prophylactic antibiotics, dosage modification or colony stimulating factor support are also reviewed.