Abstract. Inflammatory myofibroblastic tumor (IMT) is considered as a benign tumor with local aggressive course, consisting of myofibroblastic spindle cells with an inflammatory cells infiltration. IMTs are more usually found in the lung and very rarely in the mandible. We report an IMT of the mandible in a 54-year-old man. The patient complained of pain on the right side of mandible. Radiographically, the lesion was occupied in the right mandible with bone destruction. Although the initial diagnosis was an osteomyelitis, the histopathologic examination and immunohistochemistry revealed it to be an IMT. Histologically, the lesion was composed of inflammatory cells infiltration within a variably fibroblastic or myofibroblastic spindle cell background. Immunohistochemically, spindle cells stained with smooth muscle actin (SMA) and CD68 (KP1), but uniformly negative with desmin and cytokeratin.