Abstract: A failsafe cutoff valve that may be used with oil and gas wells is shown. A cylindrical body portion has a center bore extending longitudinally therethrough. A piston is located inside of the center bore. The cylindrical body portion has crossbores along a straight line that perpendicularly intersect the center bore. Received into the crossbores and secured in position are generally cylindrical flanges having a saddle shaped lower surface to conform with the center bore. An undercut in the saddle shaped lower portion provides a means for sealing along the piston. The piston is slideably retained inside of the center bore and has a transverse bore therethrough normally positioned along the same axis as the crossbores. End flanges seal around portions of the piston that extend from the center bore and prevent leakage from the center bore. The piston may be activated by any of a number of means, including a remotely located source of high pressure fluid.