Hematuria is one of the most common disorders in children. Bladder tumors are rare in children, and inflammatory pseudotumor (IP) is especially rare. We report a case of inflammatory pseudotumor of the bladder in a 13-year-old girl manifested as acute onset of non-traumatic and painless gross hematuria with impending hypovolemic shock. A huge intravesicular mass (6.5 x 3.8 cm) was noted on renal-bladder ultrasound, cystoscopy, and computed tomography. Partial cystectomy was performed to remove the mass. Pathology led to a diagnosis of leiomyoma and subsequent confirmation as an IP. To our knowledge, our case is the first presentation of bladder IP in Taiwan among the reported pediatric cases.