A prospective study was conducted to measure quality of life in newly diagnosed lung cancer patients attending a chest clinic in a large teaching and district general hospital in a geographically defined area (northern sector of Glasgow, Scotland). Quality of life was assessed at two points in time, pre-diagnosis (baseline) and 3 months after diagnosis (follow-up) using three standard measures; the Nottingham Health Profile (NHP); the European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire (EORTC QLQ-C30), and its lung cancer supplement (QLQ-LC13). Out of 133 lung cancer patients diagnosed during the study period, 129 patients (97%) were interviewed pre-diagnosis. Of these, only 63% of the patients had an active treatment. Ninety-six patients were alive at follow-up, of whom 82 patients were re-interviewed. Thus, only 82 patients who had complete data were used in the analysis. Comparing patients' pre-diagnosis and follow-up scores on the NHP, only sleep difficulties improved slightly. Patients reported increased perceived health problems of all other characteristics studied (energy, p = 0.0004; physical mobility, p = 0.0008). Similar results were observed on the EORTC questionnaires indicating that patients' functioning and global quality of life had decreased. The only significant improvement after 3 months was seen in patients' cough (p = 0.006). There were marked increases in hair loss (p < 0.0001), constipation (p = 0.007), and sore mouth (p = 0.0004). The findings suggest that patient-centred variables should receive sufficient consideration in the treatment of lung cancer. The study results clearly indicate that information on quality of life contributes to our understanding of patients' experiences of their cancer treatment.