In the present work the results of a radiotherapy protocol for the treatment of inoperable lung cancer are examined. The study was carried out on two groups of patients treated successively; the first of 140 patients by means of cobalt therapy at the normal rate, up to a dose of 4,500 to 5,000 rads in 5 weeks; the second of 221 cases by means of concentrated radiotherapy in two series of 2,000 rads in five sessions, separated by 3 weeks of rest. The results show a more rapid regression of the symptomatology in the second group of patients and a clear superiority in respect to the survival rate. The patients treated at the normal rate showed after 6 months a survival rate of 40 percent as against 60.5 percent in the second group. This difference became more evident when comparing the histologic types: 9 and 57 percent respectively for anaplastic carcinomas. The survival rate after 1 year shows a difference between the two groups which is statistically significant (16 and 21 percent respectively) (p less than 0.05). In no case did we find complications of the type of esophagitis, pericarditis or transverse myelitis. The treatment in two sessions was better tolerated both from the physical and the psychic point of view by all the patients because of the 3 weeks of rest. The superiority in regard to survival, the rapid disappearance of the symptomatology, as well as the reduction in the therapy time, justify the use of concentrated radiotherapy in the treatment of this type of tumors even in the more advanced stages of the disease.