A back-pressure bearing arrangement for a twin-screw extrusion device which prevents any back-pressure forces from affecting a gear arrangement used for driving the screws. By disposing the back-pressure bearings between the gear arrangement and the housing of the extrusion device and by providing a bearing plate, which is supported by adjustment bolts or tension rods, the bearings are frictionally disconnected from the gear arrangement housing and the back-pressure forces of the screw shafts are effectively prevented from adversely affecting the gear arrangement.