We describe a case of low-grade osteosarcoma of the jaw. The patient is a 25-year-old woman who presented with large, nontender, slowly progressive, expansile left mandibular mass. X-ray showed a predominantly hypodense mass with erosive growth pattern affecting the angle, posterior body, and ramus of the left mandible. The patient underwent left hemimandibulectomy. The tumor was a white-tan, well-circumscribed, multinodular, firm mass that measure 7.0 cm. Microscopically, the tumor was composed of bland spindle cells, with minimal cellular atypia, absent mitotic figures, very focal osteoid formation with extensive bone destruction, and soft tissue infiltration. Immunhistochemical stains for a large panel of antibodies were noncontributory. At present the patient is alive and well 7 months after surgery. Copyright 2002, Elsevier Science (USA). All rights reserved.