Since 1927, when the work of Baensch (1) drew attention to post-irradiation fractures of the femoral necks, this subject has excited a good deal of interest. Particularly has this been so in the past six years. Dalby, Jacox, and Miller (2) helped to focus American attention on the problem with their detailed study published in 1936, and recently Slaughter (3) has summarized the literature and added cases of fractures of bones other than the femora. Much emphasis has been placed on the rarity of healing of these fractures, since the great majority of them fail to heal at all, or do so only by fibrous union. Ewing (4) analyzed the possible end-results of radiation osteitis and radiation fractures and stated that complete bony healing is rare. The causes of radiation fractures have been discussed by Slaughter (3) and by Ewing (4). These writers assert that the bony changes are directly proportional to the number of x-rays absorbed and that, while bone is relatively radio-resistant, its greater density increases the absorption of x-rays and enhances the production of secondary radiation. The end-result, depending upon the number of x-rays absorbed, varies from complete recovery to an obliterative endarteritis which not only inhibits repair but predisposes to a secondary aseptic necrosis years later. The microscopic picture pro gresses through the stages of periosteal thickening, fat replacement of marrow, sclerosis and obliteration of blood vessels, bone absorption with osteoid tissue filling-in, and necrobiosis. We have observed a case of radiation fractures of both femoral necks, with subsequent evidence of bony healing. M. E. M., white female, aged 65, was referred to the radiologic service of the Hospital of the University of Pennsylvania on Dec. 10, 1934, for treatment of a basal-cell epithelioma of the urethra. Two months previously she had received 800 milligram hours of radium applied directly to the lesion. Therapy, as shown in the accompanying table, was administered in doses of 200 r in air, in our Clinic, with a constant potential machine with a half-value layer of 0.9 mm of copper. At 165 kv. this machine had a 12 per cent ripple, equivalent to 200 kilovolts-peak. The estimated total depth dose was 2,600 r to the center of each femoral neck. Because of complaints of pain in the left hip, films were made on Dec. 7, 1935. The results of examination were reported as “uncertain,” with the suggestion of a possible impacted fracture through the neck of the left femur (Fig. 1A). A re-examination on Jan. 6, 1936 (Fig. 1B) revealed a fracture through the neck of the left femur which was thought to be the result of metastasis, and between Jan. 6 and Jan. 17 further treatment was directed to this region. The factors were the same as before, 1,013 r, in air, being given to a left anterior abdomino-inguinal field, 15 × 15 cm.