A fuel cap has a valve structure for controlling both superatmospheric and subatmospheric pressures in a fuel tank. The valve has a plate or flat disc member with two apertures formed therein. A grommet is secured in each aperture. A pair of resilient valve stems are formed integrally with and on opposite sides of the plate. Each valve stem is disposed to have an end thereof operably positioned with respect to the grommet to seal the respective aperture to provide control of the pressure level in the fuel tank. One valve stem will flex to vent superatmospheric pressure and the other valve stem will flex to vent subatmospheric pressure. The plate is secured or otherwise formed integrally with the closure portion of the fuel cap.