The proper management of mandibular fractures involves reduction, rigid fixation, and immobilization to allow bone healing. Nonunion or malunion at the fractured sites is a well-known complication of fracture when the treatments are inappropriate. We present a case of left mandibular fracture due to shrapnel during the Korean War. The patients did not receive appropriate treatment at that time, so nonunion and malunion developed. Sixty years after the accident, mandibular osteomyelitis on the fracture site developed due to dental-origin inflammation. The treatment was based on relatively conservative care, such as saucerization and administration of antibiotics. There was no complication during the short-term follow-up. We present the case with literature review.