A total of 110 patients were treated with primary transitional cell carcinoma (TCC) of the urinary bladder from 1990 to 2000. During the follow-up period, which was for at least two years, four patients (3.6 percent) had subsequent upper urothelial cancer at an average of 61.5 months after initial treatment of the bladder tumor. Two of the four patients received transurethral resection several times, and the remaining two patients underwent radical cystectomy for the initial bladder tumor. The histopathological findings of subsequent upper urothelial cancer were almost the same as those for the initial bladder tumor. One patient had accompanying carcinoma in situ (CIS) and the other had adenocarcinoma with TCC. Since 1) high grade, 2) multiple, 3) recurrent and 4) occupational bladder tumors, 5) concomitant CIS, 6) vesicoureteral reflux and 7) tumor invasion of the intravesical ureters have been reported to be risk factors for developing subsequent upper urothelial cancer, patients with bladder tumors who have these risk factors should be followed-up closely.