A foldable sofa mattress and method for storing within low profile furniture. The mattress includes a transition section disposed between different collapsible sinuous spring sections. The sinuous spring sections are pivotably joined to the transition section and the sections are affixed to upper and lower grids for support. A method for storing a foldable mattress includes the steps of providing a mattress with a transition section disposed between two collapsible sections, extending opposing pairs of straps from the transition section to each of the separate collapsible sections, and bending the mattress. The method further includes the steps of flattening the two collapsible sections, placing the flattened sections on top of one another, and storing the folded mattress in a cavity.