We think of osteomyelitis as a disease of children. It is uncommon in adults, so uncommon that pyogenic osteomyelitis usually is not recognized until well along in its subacute or chronic course. The disease usually affects the flat bones of the pelvis and the spine, and its clinical manifestations are in great contrast to the more easily recognized manifestations of acute osteomyelitis in children. We report here 15 adults with pyogenic osteomyelitis of the spine. The diagnosis might have been made earlier in many of the patients if the attending internists had been better acquainted with this confusing disease. Illustrative Cases Patient 1. —This man was admitted to the University Hospitals with a large mass in the throat. It was thought to be neoplastic. The patient was a retired scrap dealer of 65 who had always been obese. For 15 years he had had diabetes mellitus so mild that he