Sarcomatoid transitional cell carcinoma (TCC) of the renal pelvis is a rare tumor with sarcoma-like components arising from the malignant transitional epithelium. The prognosis, according to previous reports, is very poor. Due to its rarity, there have been few studies concerning the treatment efficacy. We herein report a case of sarcomatoid TCC arising from the renal pelvis. A 67-year-old female was admitted with the chief complaint of bilateral flank pain. A rightrenal heterogeneous mass measuring about 5 x 7 x 10 cm was incidentally found on a clinical image. A right radical nephrectomy was performed. Histologically, a TCC in situ and another sarcoma-like area with prominent spindle cells were identified. Immunohistochemistry was positive for cytokeratin. Sarcomatoid TCC of the renal pelvis was confirmed. In spite of no ample evidence of an effective treatment, we recommend a radical, aggressive operation for early localized disease. For the tumor with advanced stage or metastasis, systemic chemotherapy with a gemcitabine-based regimen may be considered for this uncommon renal pelvic tumor due to its urothelial origin in nature.