Abstract: A movable floor self-unloading trailer has a frame with rotatable sprocket shafts supported at each end and engaged with an endless conveyor type floor comprising a series of side-by-side floor plates which are interconnected by hinge pins and are each provided with a plurality of laterally spaced bearing shoes which slide in elongated longitudinally extending channel shaped bearing rails. The movable floor includes a drive sprocket assembly characterized by a series of sprocket segments which are configured to engage the floor plates along the bearing hinge portions. The movable floor is particularly adapted for use in conjunction with a modified general cargo type truck trailer which is adapted to handle containerized as well as bulk material loads.