Osteomyelitis is usually the inflammation of bone and its marrow contents. Osteomyelitis of jaw commonly occurs as a complication of dental sepsis, but it is also seen in various other situations. It is usually a polymicrobial infection. It has been associated with multiple systemic diseases including diabetes, autoimmune states, malignancies, malnutrition, and acquired immunodeficiency syndrome. Before confirmation of osteomyelitis, one should rule out tooth as source of infection. The medications linked to osteomyelitis are steroids, chemotherapeutic agents, and bisphosphonates. Different terminologies and classification systems are used, based on a variety of features such as clinical course, pathological__ampersandsignndash;anatomical or radiological features, etiology, and pathogenesis. It may be classified as acute, subacute or chronic, depending on the clinical presentation. Osteomyelitis of jaw is still a fairly common disease in maxillofacial clinics despite the introduction of new antibiotics and the improvement of dental care. The disease may occur at any age, with most common site being mandible. This is a case of an adult patient with chronic suppurative osteomyelitis (CSO), who reported to our department with pain and swelling in molar region of the mandible on right side. Here we report a case with detailed clinical, radiographical and histopathological features with differential diagnosis and treatment.