The chapter outlines different types of osteomyelitis of the jaw bones. It describes definition, predisposing factors, etiology, and pathogenesis, microbiology and various classifications of osteomyelitis of the jaws. It describes acute and chronic forms of osteomyelitis in detail. The chapter mentions hyperbaric oxygen (HBO) in the treatment of osteomyelitis and various other forms of treatment in the management of osteomyelitis. The chapter deals with infantile osteomyelitis, Garre’s Sclerosing Osteomyelitis, and Actinomycotic Osteomyelitis. The chapter also mentions detailed account of tuberculous osteomyelitis of the jaw bones and osteoradionecrosis (ORN) of jaw bones and describes the pre-irradiation and post-irradiation care of patients.