The aim of palliative thoracic radiotherapy in patients with advanced non-small cell lung cancer (NSCLC) is to alleviate symptoms. This study was designed to determine whether any patients achieved long-term survival after this treatment. In Edinburgh, between 1974 and 1993, 4531 patients were treated with palliative radiotherapy for NSCLC, receiving ten fractions or fewer. We reviewed the case notes of the long-term survivors. Sixty-one (1.3%; 95% confidence interval (CI) 1.0-1.6) patients survived for more than 5 years; 43 (70%) had histological confirmation of cancer; 28 (46%) had stage Stage I or II, 28 (46%) Stage III and one Stage IV disease; 53 (87%) patients were treated with doses of 30-35 Gy in ten daily fractions, seven (12%) received 20 Gy in five daily fractions and one received a 10 Gy single fraction. Forty-two (69%) patients had a radiological complete response, 16 (26%) a partial response and the remainder stable disease. Clinically significant radiation pneumonitis occurred in one (2%) patient, radiation myelopathy in two (3%) and multiple rib fractures in one (2%). There did not appear to be an association between long-term survival and a radiosensitive phenotype. On univariate analysis, long-term survival was more frequent in patients receiving ten-fraction regimens than in those who underwent a shorter course of radiotherapy (chi 2 = 19.5, P < 0.001). Thirty-four (0.8%; 95% CI 0.6-1.0) patients were disease free at death or at last review (median 10 years; range 5-17). We conclude that palliative thoracic radiotherapy produces long-term survival in 1.3% and personal cure in up to 1% of patients with advanced NSCLC.