Three cases of tardive myelopathy were identified among more than one thousand patients treated for tumors by X-rays at the Institute of Radiology of the University of Florence during the period 1974-83. In two of these, the clinical picture was that of a partial Brown-Séquard syndrome while in the third case it corresponded to a transverse myelitis. The myelopathy of the former patients can be attributed to the total radiation dose, which was very close to the tolerance limit. The third patient's disturbance, instead, involved additional factors of individual hypersensitivity of connective vascular tissue in response to the X-ray treatment. These cases, while few in number and lacking pathological investigation, call attention to this iatrogenic disorder which, though rare now thanks to progress in limiting radiation exposure, has not yet disappeared.