The incidence of unexpected ureteral carcinoma on mapping and recurrence of upper urinary tract urothelial cancer was examined in 160 patients who had undergone total cystectomy for vesical cancer and complete mapping of the specimens between May, 1978 and June, 1986 at our Center. Unexpected carcinoma in the ureteral stump was found in 5 patients (3.1%) and recurrent cancer in the upper urinary tract developed in 2 (1.3%) of the 160 patients. The incidence was higher in the recurrent bladder cancer cases, and also higher in patients with non-visible, high grade and superficial tumors of the bladders.