Abstract: A gasoline filter for the entranceway to a gas tank filler tube has three preferred embodiments. The first includes a semipermanently mounted cap having a bore in which there is disposed a removable cylindrical filter element. The element is seated on a rotatable retainer for alignment with an eccentric opening in the filler tube entranceway. Normally closed resiliently mounted doors seal the entranceway but permit a gas pump nozzle to be inserted into the entranceway. The second embodiment has an integral hinged door atop the filter element for use with a conventional gas cap. The third embodiment has dual hinged doors mounted within the bore of the filter element arranged to be opened automatically by a pusher bushing when a gasoline dispensing nozzle is inserted in the gas tank filler tube.