Abstract: A truck trailer has a movable load-supporting floor including a conveyor belt for fore and aft movement of cargo along the truck trailer, permitting cargo to be loaded into or unloaded from the trailer with minimal expenditure of human labor. The conveyor utilizes a pair of rigid, elongated members positioned along the sidewalls of the truck, spaced from one another, and generally parallel to one another. A plurality of elongated parallel rollers are closely spaced to one another and have their ends rotatably mounted to the elongated members, permitting rotation of the rollers about their longitudinal axes. The conveyor belt is supported by the rollers and mounted thereon for fore and aft movement along the trailer as the rollers rotate about their axes. Sprockets are fixed to the ends of each individual roller. A pair of endless chains extends along the lateral sides of the belt and engages the sprockets at each end of the rollers to rotate the rollers.