Abstract: An extensible grain auger includes a casing defined by co-axial telescoping sections, with an inlet at one end and an outlet at the other end of the casing, a pair of inter-connected auger tubes rotatably mounted in the casing, the flight of one tube being threadable into the auger flight of the other tube; and an extension tube and screw assembly rotatably mounted in the auger tubes, the extension tube extending out of the casing at one end and the screw being connected to a nut in the tube and to the other end of the casing, so that one casing section can be extended and retracted relative to the other casing section.