Transitional cell carcinoma of the bladder is a rare entity in childhood. We report on a 10-year-old boy with transitional cell carcinoma of the bladder who presented with gross hematuria. Ultrasonography revealed a papillary lesion in the bladder. Cystoscopic evaluation showed a papillary lesion with a thick stalk located just above the right ureteral orifice. Because the lesion was suspicious for at least lamina propria invasion, a single dose of mitomycin C was instilled after resection. Pathologic evaluation of the specimen was reported as grade 2 transitional cell carcinoma of the bladder with lamina propria invasion. Immunohistochemical staining with p53 and Ki-67 was performed for further evaluation.