A 15-year-old male was referred to our hospital with the chief complaint of gross hematuria. Cystoscopic examination revealed a papillary tumor on the posterior wall. Transurethral resection of the bladder tumor was performed. Histological examination of the excised tumor showed transitional cell carcinoma, grade 1, pTa. Recurrence has not been observed for about 2 years after the operation. We investigated 54 previously reported Japanese cases of bladder cancer before age twenty including the present case.