Since 1930, 117 patients with well-documented osteogenic sarcoma of the skeleton and the soft tissues occurring in patients older than 60 years have been diagnosed and treated at Memorial Hospital for Cancer and Allied Diseases. This number represents approximately 10% of all osteogenic sarcomas treated at this Medical Center. Slightly more men than women (68 versus 49, respectively) were affected, with a mean and a median age of 68 and 66 years, respectively, ranging from 60 to 86 years of age. One hundred one lesions occurred in the skeleton and 16 in extraosseous sites. In contrast to osteogenic sarcoma in children and adolescents, where more than half of the tumors arise in the fastest-growing bony sites around the knee, this region was involved in only 14.5% of the older patients. In this latter age group, the axial skeleton was the most commonly affected (27%), in addition to the craniofacial bones (13%) and extraskeletal sites (11%). Contrary to expectations, the lytic destructive skeletal lesions were three times more common than any other radiographic presentation, with the fibrous (38%), the osteoblastic (25%), and the cartilaginous (17%) sarcoma variants predominating over all others on histologic examination. Whereas 97% of osteogenic sarcomas occurring in patients younger than 21 years arise anew, without any pre-existent osseous disease, in this study's older population, sarcomas were more frequently (56%) secondary to other bony conditions, such as Paget's disease, or followed irradiation. Five-year survival estimates were strongly dependent on whether the patients had primary de novo osteogenic sarcomas (37%) or whether the sarcomas arose secondary to other skeletal conditions (7.5%). There are no significant survival differences between patients treated before or after 1974, when adjuvant and neoadjuvant chemotherapy started to make its positive impact in the treatment of osteogenic sarcoma in children and adolescents.