Abstract: The box spring and box spring structure include a versatile frame made at appreciably lesser expense than presently known frames of equal rigidity and light weight. End rails of rectangular cross section carry no springs and are arranged completely underneath and overlap the side rails at the frame corners. All the rails have upper surfaces planar throughout their widths, those of the end rails being in secured engagement with the lower wide faces of the side rails at the frame corners to dispense with braces. The cross slats are parallel to each other and spaced any desired distances apart, equal or unequal. The end slats which carry the end rows of springs are arranged in close proximity to the respective end rails and are spaced above the end rails while extending inwardly enough in width to locate said spring rows in the proper position for upholstering.