We report a case of transitional cell carcinoma in the left renal pelvis, which occurred in a 24-year-old man. He had been treated with cyclophosphamide (CPM) for a period of 27 months for retroperitoneal rhabdomyosarcoma diagnosed at the age of 10. At first 1.2 g CPM had been given twice intravenously for 3 months, followed by oral administration of 41 g CPM for 23 months. Drip infusion pyelography revealed a filling defect in the left renal pelvis. A left renal pelvic tumor was strongly suspected on computerized tomography and magnetic resonance imaging. Left nephroureterectomy was then performed. Histological diagnosis of the left renal pelvic tumor was transitional cell carcinoma, grade 2, pT1N0M0. No recurrence was defected 17 months later. This case seems to be the second case of cyclophosphamide-induced upper urothelial carcinoma reported in Japan.