Horseshoe kidney, afrequent abnormality of renalfusion, is often complicated with hydronephrosis, renal stone and urinary infection. This report concerns a horseshoe kidney with transitional cell carcinoma. The patient presented as a painless, gross hematuria, diagnosed to be horseshoe kidney with left renal pelvis and lower calyx tumor. The vascular anatomy was confirmed by renal angiography. Left nephroureterectomy and bladder cuff excision was sucessfully performed through a transperitoneal approach for vascular control and precise demarcation of the line of resection at the isthmus. Follow- up by computerized tomography nine months post-operatively revealed no tumor recurrence.