Osteomyelitis is the inflammatory disease occured in the bone, involving a bone marrow, a Harversian system and the underlying cortical bone. Osteomyelitis is divided into acute and chronic osteomyelitis. Chronic osteomyelitis. is presented as a pain, swelling, pus discharge and radiographic change. The pathogenesis of osteomyelitis occcuring in the facial bone is predominately due to odontogenic microorgarnisms, Staphylococcus, resulted in odontogenic infection or post-traumatic infection. The mandible is the most commonly involved facial bone and the bones in the middle of third of the face is rare because of a abundant blood supply. Moreover, Osteomyelitis occuring in the zygoma is extremely rare. In our department, we report the case that osteomyelitis occuring in the zygoma with diabetes is resulted by odontogenic maxillary sinusitis.