A prospective follow up was carried out on 479 consecutive patients who underwent lung resection for non small cell primary bronchogenic carcinoma between 1980 and 1987 under the care of one surgeon at Guy's Hospital and Brook Hospital, London. The mean age of patients was 61.8 years; 16.9% were aged 70 years or over. Of the 479,237 patients had stage I disease, 108 patients stage II disease, and 134 patients stage III. Lobectomy was performed in 280 patients, pneumonectomy in 191, and wedge resection in 8. Operative mortality was 5% overall, 6.8% following pneumonectomy and 3.9% following lobectomy. There was no operative mortality following wedge resection. Old age did not affect operative mortality. Overall actuarial survival was 76.2% and 39.8% at 1 year and 5 years postoperatively, respectively (stage I: 86% and 55%; stage II: 77.8% and 35.5%; stage III: 57.5% and 16.2%). There were statistically significant differences in survival between the stages. Five-year actuarial survival was 45% for squamous cell carcinoma, 36.3% for adenocarcinoma, 31.9% for dimorphic carcinoma and a 21% for undifferentiated carcinoma. There were statistically significant differences in survival between undifferentiated carcinoma and each of the other cell types. The favourable survival in stage I disease lends weight to the concept that there is hope for cure in patients with early non small cell lung cancer.