Ischemia and the accompanied hypoxia significantly impair the function of the urinary bladder, which is further damaged by ischemia/reperfusion (I/R) injury following the re-establishment of the blood supply. Current evidences have confirmed that blood flow of the bladder is decreased by bladder outlet obstruction (BOO) and acute overdistention and that functional impairment of the urinary bladder following chronic BOO and acute overdistention might partly come from tissue ischemia and ischemia/reperfusion injury. Antioxidants, free radical scavengers or substances inhibiting I/R injury may reduce bladder damages caused by BOO or overdistention.