A 70-year-old man with dysuria was referred to our hospital. Computed tomography scan and magnetic resonance imaging demonstrated a large solid tumor in the retrovesical space. Transurethral needle biopsy revealed leiomyosarcoma. Since the size of the tumor decreased markedly by intraarterial chemotherapy with cisplatin, methotrexate and pirarubicin, in combination with radiotherapy (40 Gy), surgical extirpation of the tumor was performed. Neither infiltration to the adjacent organs or lymph node metastasis was recognized. The patient had been free of recurrence for 12 months after operation.