A case of retroperitoneal tumor presenting with gross hematuria is reported. A 62-year-old female consulted our clinic with the chief complaint of gross hematuria. On physical examination, a goose-egg sized tumor was palpable in the left flank region. Drip infusion pyelography and computerized tomographic scan showed left retroperitoneal tumor which deviated the left kidney upwards. Percutaneous needle biopsy of the tumor revealed no malignancy. Total resection of the tumor was performed subsequently. A yellowish solid tumor was macroscopically encapsulated by fibrous tissue, weighed 230 g and 6 x 7 x 10 cm. Histopathological diagnosis was malignant schwannoma. After operation, the hematuria stopped without any treatment and deviation of the left kidney was improved. Soft tissue tumor should be treated by adjuvant chemotherapy with irradiation because of its high frequency of recurrence and metastasis. Combined chemotherapy with VCR, ADR, CPM and DTIC (CYVADIC) was performed and she is in good health at 1 year after operation.