An assemblable mattress support can be shipped with all of its components compactly packed into the headboard. The mattress support includes a foldable longitudinal bar, a lateral bar, side panels, wooden slats, block legs and a footboard, all of which fit inside a compartment in the headboard. In an assembled state of the mattress support, a first connector at one end of the longitudinal bar attaches to a third connector on the outside of the headboard. A second connector at the other end of the longitudinal bar attaches to a fourth connector on the footboard. The middle of the lateral bar connects to the middle of the longitudinal bar. The block legs are attached to the bottom sides of the headboard and footboard. The slats are attached to one another by fabric ribbons and are placed in parallel over the longitudinal bar and support ledges on the side panels.