A case of leiomyosarcoma in the maxilla is presented together with a review of the literature. The most commonly encountered symptom at the early stage of oral leiomyosarcoma is a slowly enlarging, nonulcerated and painless mass. This tumor shows high incidence of local recurrence or metastasis, and poor prognosis. The histological confirmation of leiomyosarcoma seems difficult in the routine examination using biopsy specimen. Special staining methods and immunohistochemical analysis are useful for diagnosis of this tumor. The tumor slightly responded to chemotherapy consisting of adriamycin and cyclophosphamide.