Myelopathy is an uncommon complication of radiotherapy. Radiation myelopathy is principally a white matter injury of the spinal cord induced by ionizing radiation after a certain latent period. Several factors, such as radiation dose, fractination or linear energy transfer, modify its occurrence and severity. A 56-year old man with gastric adenocarcinoma underwent chemotherapy and radiotherapy following tumor excision. Two months later he developed a progressive paraparesis. This case is a model for the patiens that develops neurologic dysfunction after radiotherapy.