A retrospective review was made of the pretreatment radiographs of 20 patients with well-documented primary lymphoma of bone. Nine radiographic signs were defined, and the presence or absence of each was recorded for each patient. When the radiographic findings were compared with disease-free survival for each patient, it was found that patients who had a relapse had a higher mean number of positive radiographic signs than those who remained disease free (p less than 0.02). Also, those who relapsed early had more positive signs than those who relapsed late (p less than 0.05). Certain signs, i.e., pathologic fracture, layered periosteal new bone, broken periosteal new bone, cortical breakthrough, soft-tissue mass, and soft-tissue swelling, were more helpful than others for making a prognosis. These signs appear to be related to radiologic evidence of imminent or actual soft-tissue extension of the tumor.