The present invention provides a urethral prosthesis including a substrate, an inflatable pillow attached to the substrate, a pressurized reservoir in fluid communication with the pillow and a restrictor. Upon compression of the inflatable pillow, inflating agent is transferred from the inflatable pillow to the pressurized reservoir. Upon terminating compression, inflating agent returns to the inflatable pillow. The urethral prosthesis may be implanted such that the inflatable pillow prevents unintentional voiding of a patient's bladder.