Osteomyelitis of the mandible, a serious complication of untreated odontogenic infection has been reported. This case report describes an interesting presentation of chronic suppurative osteomyelitis (CSO) of the mandible in a 13 years old anaemic male patient. Investigations revealed inversion of his permanent teeth leading to trans-cutaneous extra-oral eruption along with marked destruction of mandible on the affected side. The treatment included a pre surgical course of antibiotics followed by the removal of the retained second premolar tooth, surgical debridement of the affected bone, and resection of the cutaneous sinus tract. The post-operative healing was uneventful. A combination of antibiotic therapy and surgical debridement were effective in the treatment of chronic suppurative osteomyelitis.