Abstract: A convertible bedding assembly and mattress in which a foldable frame assembly is operatively attached to a sofa or chair portion for movement between an expanded position and a folded position. A first mattress is disposed on the frame assembly and a second mattress extends over the first mattress in at least said expanded position, with the width of the second mattress exceeding the width of the first mattress and being at least equal to the width of the frame assembly. The second mattress is a composite assembly including a pair of overlying flexible resilient pads and a wire layer sandwiched between the pads. A strip of rigid material extends along the edge portions of the wire layer, and the latter edge portions are wrapped around the strips and secured thereto.