The author observed a case of the malignant fibrous histiocytoma of the mandible in 23 aged male patient, who had come to the Infirmary of Dental College, Yonsei University. With the help of careful analysis of radioraphic and clinicopathologic findings, the author had obtained the results as follows. 1. Lesion occured at 22 years of age. 2. Traumatic history or other special predisposing factors were not seen. 3. Lesion appeared as a intra osseous primary tumor not showing any metastatic change. 4. The author have concluded this disease as a malignant fibrous histiocytoma of the mandible according to serial findings.