The aim was to describe self-reported health-related quality of life (HRQoL) in patients with advanced non-small cell lung cancer and to investigate the associations to stage of disease, age, gender, weight loss and performance status. Further, the study aimed to compare patients' HRQoL with that of the Swedish general population. Data on HRQoL were collected within a multi-centre randomised controlled trial. A total of 334 patients were included between 1998 and 2001. The European Organization for Research and Treatment of Cancer Quality of Life Questionnaire-Core Questionnaire (EORTC QLQ-C30) and Lung Cancer Questionnaire (EORTC QLQ-LC13) were used to assess HRQoL. HRQoL data for comparison with the Swedish population were derived from a random sample of the Swedish population. Patients reported a markedly impaired HRQoL compared to the normal population. There were statistically and clinically significant differences with regard to almost all QLQ-C30 functional and symptom scales. Global health status, physical functioning, role functioning and emotional functioning were markedly deteriorated. The most prominent symptoms were dyspnoea, fatigue, coughing, insomnia, appetite loss and pain. A low performance status, younger age, female gender and a more advanced disease were independently associated with a worse HRQoL. Additional studies are required to gain increased insight into this seriously ill group of patients and their need of supportive care.