Abstract: A box spring assembly comprises a horizontal rectangular frame, a generally horizontal mattress support deck disposed a predetermined distance above the frame, and a plurality of deck support springs arranged between the deck and the frame to yieldably support the deck. The deck includes a plurality of long and cross deck wires each having notches. The long and cross deck wires are oriented in a criss-cross fashion engaging each other at the notches, and a plurality of deck support springs having notched deck attaching portions engaged with the notched intersections of the wire members. At least one of the deck attaching portions includes a pair of end straight wire sections arranged in a side-by-side relation with a spaced pair of the deck wire members and arranged in a supporting relation with spaced portion of another one of the deck wire members that intersects the spaced pair interlocking the deck wire members and the straight wire section together.