Abstract: A roll out tarp cover assembly is situated across the front end of a truck box and contains a roller upon which the tarpaulin or cover engages. It is operated by a retractable hand crank at one end. Transverse stiffeners are secured to the cover with the ends engaging side rails secured to the upper edges of the truck box sides and the cover may be detachably secured by the free end thereof to the upper edge of the tailgate by snap fasteners, magnets or the like. The side rails have drainage holes and a rain shedding outer shroud fasteners are slideably engageable within a track formed on the under side of the side rails in order to secure the rails to the upper edges of the truck box.