Chronic myelogenous leukemia (CML), osteomyelitis, and chronic periodontal diseases affect elderly people in common. These disorders also have direct/indirect associations between them. CML is a pluripotential stem cell disease and usually presents as an increased incidence of infections, generalized gingival hypertrophy, and gingival bleeding. These may be the initial presenting features of the disease. Osteomyelitis is an inflammation of the bone and bone marrow in which reduced vascularity and osteocyte destruction occur. The clinical presentation and course depend on the virulence of the micro-organism involved and the patient's resistance. The reason that osteomyelitis varies in elderly is chronically impaired immune host response. We report an 83-year-old man with severe gingival bleeding who was referred to periodontology clinic for consultation. He had uncontrolled gingival bleeding from buccal side of lower right second molar. We extracted involved tooth and removed granulation tissues from cavity. Healing was satisfactory. Our preliminary diagnosis of osteomyelitis was confirmed by CT, and on pathological examination, he was also diagnosed as having CML. Treatment procedures must be individually designed, especially for elderly patients. To avoid secondary infections and complications, it is imperative that elderly patients have regular examinations and not wait for problems to occur.