A shelving system having tubular frame members and plastic shelves, the shelves having frame receiving regions for receiving ends of the frame members. The shelves and frame members are connectable by insertion of the frame members into the frame receiving regions to form an openly configured, assembled shelving unit in which the shelves are connected to one another in vertically spaced relationship by the frame members. The shelving system has at least one closure member. The assembled shelving system and the at least one closure member both have an integrally molded connector structure. The integrally molded connector structures enable the at least one molded plastic closure member to be connected to the assembled shelving unit after the shelving unit has been assembled.