Primary osteosarcoma of bone has originated in the spine in only a few patients. This report concerns twenty-seven of thirty patients who had the original diagnosis made and surgical treatment, if any, performed at the Mayo Clinic. The patients' ages ranged from eleven to eighty years. Pain in the area of involvement was the first symptom in all patients. In addition, nineteen patients (70 per cent) had neurological symptoms and signs when they were first seen. All patients had a surgical biopsy of the lesion, often combined with decompressive laminectomy. Twenty-one of the twenty-seven patients received postoperative radiation therapy in various dosages. Only five patients received adjunctive chemotherapy. All but one patient died of the disease, with a median length of survival of ten months (range, one to thirty-eight months). Although rare, osteosarcoma of the spine can usually be suspected on roentgenograms, and then the most aggressive therapy is justified.