A case of unusual tumor of renal pelvis and ureter is reported. A 82-year-old man was admitted with the chief complaint of gross hematuria. He was diagnosed with bladder tumor and right renal pelvic and ureter tumor by bladder biopsy (TCC G2) and radiological examinations. Right nephroureterectomy was performed after transurethral resection of bladder tumor (TUR-Bt). Histological findings of renal pelvic and ureteral tumor were squamous carcinoma with pseudosarcomatous stroma (so-called carcinosarcoma). Tumor cells showed mostly a sarcomatoid spindle pattern and partly apparent SCC. He was discharged without adjuvant therapy and no recurrence was found for 7 months after operation. In our case, CA19-9 was useful as a tumor marker. Such disease has been confused with true carcinosarcoma or sarcomatoid carcinoma and should be distinguished from them. We reviewed 18 case reports of true carcinosarcoma or sarcomatoid carcinoma of the renal pelvis.