Abstract: A sphincter valve for controlling the flow of fluid through a fluid delivery line has a body molded of a unitary piece of substantially flexible silicone material. The body is formed with an outer shell, and interior tube disposed within said outer shell, an end portion, and a pressure chamber defined between the outer shell and the interior tube. A separate end cap is secured to and closes the end of the body opposite the end portion thereof and a central passageway extends through the interior tube and through the ends of the valve. In use, the valve is spliced in a fluid delivery line and the pressure chamber is coupled to a source of selectively deliverable pressurized air. When pressurized air is forced into the pressure chamber, the inward force created by the pressure collapses the interior tube onto itself shutting off flow through the valve.