Abstract: A truck storage box device for use in the bed of a pick-up truck, having a bottom, and a plurality of interconnected sides extending upward from the periphery of the bottom which intersect to provide an open top for access to the interior formed between the bottom and the sides. The bottom and sides form an open container in which a plurality of spaced pairs of opposed, elongated rails extend horizontally along opposite interior wall portions thereof in a spaced relationship with the bottom. Each pair of opposed rails is arranged to slidably receive and support a number of elongated trays thereon. Each of the trays is arranged to extend between pairs of opposed rails. Collectively, the pairs of opposed rails form a vertical array in which a number of trays can be supported on each pair of opposed rails in a vertically stacked arrangement from which one or more intermediate trays may selectively be slid horizontally from within the stacked vertical arrangement for access to their particular contents.