Polypoid cystitis without a history of catheterization is rare. We report a case in which the condition occurred in a 16-year-old girl complaining of dysuria, urgency, frequency, and a residual urine sensation. Cystography revealed a large intravesical filling defect with bladder distension, while sonography and CT demonstrated a large, inhomogeneously enhancing solid mass in the urinary bladder.