Adequate management of symptoms in adults with lung cancer is an important focus for clinical interventions. Knowledge of symptom prevalence and distress can be used to develop empirically based interventions that can potentially reduce distressing symptoms and improve quality of life. The purposes of this study were to describe which symptoms are most distressing, describe the prevalence of symptoms in adults receiving treatment for lung cancer, identify how symptoms change over time, and identify patient-related and clinical characteristics related to symptom distress. Data were available from 117 patients. Fatigue and pain were the most distressing symptoms for each group and at each time. Significant differences in distressing symptoms among the treatment groups were noted for nausea, fatigue, bowel pattern, and concentration at entry into the study and difficulty with appetite at 6 months. Many of the individual symptoms demonstrated a decrease in distress from 0 to 3 months and then an increase in distress levels from 3 to 6 months. Many of the individual symptoms were associated with demographic covariates and treatment group values but no consistent pattern emerged over time except for baseline symptom distress. Symptom distress at entry to the study was a strong predictor of nine distressing symptoms at 3 months and seven distressing symptoms at 6 months. Questionnaires such as the SDS may be useful as screening instruments to target those who need more intensive interventions. Copyright © 2003 John Wiley & Sons, Ltd.