Abstract: A mobile combine harvester comprises a reaping assembly comprising a laterally extending platform, a cutter bar at the forward edge of the platform, a reel above the cutter bar and a screw conveyor for transporting cut grain to a discharge point. A thrashing assembly which is inclined upwardly rearwardly receives cut grain directly from the reaping assembly and comprises a cylindrical casing, a cylindrical screen in the casing and a rotor in the cylindrical screen. The rotor comprises a cylindrical portion provided with a helically extending vane carrying pins or blades for thrashing the grain. At the rear end of the rotor there is a coaxial radial fan which discharges straw from which grain has been recovered. Below the cylindrical screen there is a grain-collecting trough with a screw conveyor for transporting the grain to the rear where it is delivered directly to a cleaning assembly comprising a vibrating screen and blower for removing light waste.