Radiotherapy was applied to 256 patients with lung cancer treated in the Institute of Oncology in Krakow in the years 1959-1967. Malignancy had been confirmed throughout in organs of the chest cavity, and diagnosed by microscopic examination. Eleven patients, i.e. 4%, survived 5 years. Survival rate was related to the stage of the disease and the microscopic pattern. Some patients were cured after irradiation of lung cancer, using nominal doses lower than the lethal dose for squamous cell cancer. The specific physical conditions of radiation absorption in the chest cavity evidently made the effective dose inside the cavity much higher than the nominal dose.