Inflammatory myofibroblastic tumor (IMT) is a rarely described tumor of unknown etiology and pathogenesis. It occurs primarily in the lungs, but has occurred in other extra-pulmonary sites. Histologically these lesions appear as an inflammatory infiltrate within a variably myofibrotic background. Current evidence shows that inflammatory myofibroblastic tumors are neoplastic processes resulting from chromosomal translocations that often cause an overexpression of ALK kinase, which is often assessed using immunohistochemical studies. Currently, the biological behavior of oral inflammatory myofibroblastic tumor is still uncertain. This article describes the clinical, histological, and operative features of a case of IMT of the Mandible. I report such a case of inflammatory myofibroblastic tumor of the mandible in a 16-year-old girl. The patient presented with a large aggressive ulcerative soft tissue mass of 3 year duration in the rigth mandibular molar gingiva. Histologically, section show; loosely arranged myofibroblasts in an edematous and myxoid background with plasma cells, lymphocytes, eosinophils, and blood vessels and overlined by ulcerative skin, no necrosis or mitosis. Immunohistochemically, the fibroblastic or myofibroblastic spindle cells were positive for vimentin, á- smooth muscle actin, and Ki-67 (MIB-1) but negative for desmin, pan-cytokeratin, S-100 protein, CD34, CD68, CD99, bcl-2, a-catenin, estrogen receptor, progesterone receptor. These spindle cells were focally and weakly Ki-67- (MIB-1-) positive. A pathological diagnosis of inflammatory myofibroblastic tumor was made. The postoperative course was uneventful, and the patient has had no recurrence in the 1 year follow-up period. Although no evidence of oral inflammatory myofibroblastic tumor recurrence or malignant transformation has been reported, it has been observed that in inflammatory myofibroblastic tumors of other regions, a prolonged follow-up is necessary after surgical resection.