Early diagnosis and treatment of osteomyelitis provide good prognosis and prevent severe complications. Therefore, it is important to early diagnose and treat before the bony changes are observed in conventional radiograms. Authors experienced three cases of early osteomyelitis, and scintigrams were useful to differentiate them from other diseases. The purpose of this report was to aid in the early diagnosis and treatment of osteomyelitis occurred in the jaws. The characteristic features were as follows: 1. In clinical examination, the patients complained mild pain and localized swelling in the jaws. 2. In radiographic findings, the conventional radiograms showed relatively mild bony changes in the jaws. 3. The more severe periosteal reactions were observed in radiograms in children than in adult patient. 4. It showed marked increased uptake of radioisotopes in all scintigrams. 5. The three phase bone scannings were helpful to differentiate osteomyelitis from soft tissue diseases.